tree-wide: Don't explicity disable copy-on-write when copying images

Since the copy helpers now copy file attributes as well, let's not
explicitly disable copy-on-write anymore when we copy an image. If
the source already has copy-on-write disabled, the copy will have it
disabled as well. Otherwise, the copy will also have copy-on-write
enabled.

This makes sure that reflinks always work as reflink is only supported
if both source and target are copy-on-write or both source and target
are not copy-on-write.

copy: Copy file attributes as well

Let's make sure we copy all file attributes that can be copied as
well.

Make read_attr_path() more generic

Let's make this an openat() like function so it can be used in more
scenarios.

repart: Create disk image file with copy-on-write disabled on btrfs

COW on btrfs generally does not play well lots of random writes so
let's make the disk images generated by repart NOCOW by default on
btrfs like we do elsewhere across the codebase.

repart: Make partition files NOCOW if the disk image is NOCOW

On btrfs, reflinks into a disk image that has copy-on-write disabled
only work if the source has copy-on-write disabled as well so let's
make sure that's the case if the disk image has copy-on-write disabled.

fs-util: Add XO_NOCOW flag

Let's add a flag for xopenat() that immediately makes a file NOCOW
after opening it if it's supported.

fs-util: Clean up properly in xopenat_full() on labelling error

If we fail to relabel the file, we should unlink the file or directory
again, so let's make sure we do that.

fs-util: Handle dangling symlinks in openat_report_new()

openat() will always resolve symlinks, except if O_NOFOLLOW is passed
or O_CREAT|O_EXCL is passed. This means that if a dangling symlink is
passed to openat_report_new(), the first call to openat() will always
fail with ENOENT and the second call to openat() will always fail with
EEXIST.

Let's catch this case explicitly and fallback to creating the file with
just O_CREAT and assume we're the ones that created the file. We can't
resolve the symlink with chase() because this function is itself called
by chase() so we could end up in weird recursive calls if we'd try to do
so.

test-fs-util: Modernize openat_report_new() test

test-id128: Use new assertion macros

test: Add ASSERT_EQ_ID128() and ASSERT_NE_ID128()

test: Add ASSERT_FAIL()

mkosi: Update to latest

Includes the required fix to make mkosi copy NOCOW disk images properly.

Merge pull request #33535 from neighbourhoodie/tests/dns-cache

Tests for DnsCache functions

Merge pull request #33534 from neighbourhoodie/tests/dns-query

Tests for DnsQuery functions

core: clean up Set/LoadCredential= parsers

Make logging consistent, plus introduce helper function
for adding creds to ExecContext.set_credential too.

mkosi: Bump device timeout even more

I still manage to hit it in some cases so let's bump again.

Merge pull request #33533 from neighbourhoodie/tests/dns-synthesize

resolved: tests for dns_synthesize_family() and dns_synthesize_protocol()

resolved: tests for dns_synthesize_answer()

sd-dhcp-server: persist hardware addresses in leases

resolved: tests for dns_query_string()

resolved: tests for dns_query_go(); multiple search domains for dns_query_candidate_notify()

resolved: refactor environment management in dns_query_go() tests

resolved: tests for dns_query_go() when configured with search domains

resolved: tests for dns_query_go() when no scopes are available

resolved: tests for dns_query_go() using a bypass query

resolved: tests for dns_query_go() -- with and without network link

resolved: tests for dns_query_process_cname_one(); no match, DNAME, utf-8 handling

resolved: tests for dns_query_process_cname_many()

resolved: tests for common usage of dns_query_process_cname_one()

resolved: tests for dns_query_make_auxiliary()

resolved: tests for dns_query_new()

resolved: tests for dns_cache_lookup() clamping the TTL

resolved: tests for dns_cache_put() for  NXDOMAIN with no SOA

resolved: test that pseudo classes and types are not cached

resolves: tests for dns_cache_prune()

resolved: tests for dns_cache_check_conflicts()

resolved: tests for dns_cache_export_shared_to_packet()

resolved: tests for dns_cache_lookup(); mDNS and multiple matching entries

resolved: tests for dns_cache_lookup() returning the most recent input

resolved: tests for dns_cache_dump()

resolved: test cache misses

resolved: tests for dns_cache_lookup() for NXDOMAIN

resolved: first test for dns_cache_lookup()

resolved: tests for dns_cache_dump_to_json()

resolved: check that adding an expired response removes cache entry

resolved: tests for dns_cache_put(); CNAME success and name error

resolved: tests for dns_cache_put() with non-matching class, type, name

resolved: refactor DNS answer construction for cache tests

resolved: test for dns_cache_put() with empty answer

resolved: tests for dns_cache_put() with different RCODEs

resolved: tests for dns_cache_put(); successful A query

Co-Authored-By: jan@neighbourhood.ie

Merge pull request #33531 from neighbourhoodie/tests/dns-zone

resolved: tests for dns_zone_lookup()

resolved: tests for dns_zone_remove_rrs_by_key()

resolved: tests for dns_zone_remove_rr()

resolved: tests for dns_zone_put()

Merge pull request #33530 from neighbourhoodie/tests/dns-search-domain

resolved: tests for dns_search_domain_find()

resolved: tests for search domain marking and unlinking

resolved: extract function for checking search domains

resolved: tests for dns_search_domain_unlink()

resolved: tests for dns_search_domain_new()

Merge pull request #33529 from neighbourhoodie/tests/dns-link

Tests for DNS Link functions

Merge pull request #33528 from neighbourhoodie/tests/dns-answer

resolved: tests for dns_answer_order_by_scope()

resolved: tests for dns_answer_has_dname_for_cname()

resolved: tests for dns_answer_dump()

resolved: tests for dns_answer_{copy,move}_by_key()

resolved: tests for dns_answer_remove_by_answer_keys()

resolved: tests for dns_answer_remove_by_{key,rr}()

resolved: tests for dns_answer_merge() and dns_answer_extend()

resolved: tests for dns_answer_find_soa()

resolved: tests for dns_answer_add(), dns_answer_match_key()

Merge pull request #33526 from neighbourhoodie/tests/dns-question

resolved: tests for dns_question_merge()

resolved: tests for dns_question_first_name()

resolved: tests for dns_question_dump()

resolved: tests for dns_question_cname_redirect()

resolved: tests for dns_question_is_equal()

resolved: tests for dns_question_is_valid_for_query()

resolved: tests for dns_question_matches_cname_or_dname()

resolved: tests for dns_question_matches_rr()

resolved: tests for dns_question_new_service()

resolved: tests for dns_question_new_reverse()

resolved: tests for dns_question_new_address()

resolved: tests for dns_question_add()

Merge pull request #33525 from neighbourhoodie/tests/dns-rr

resolved: tests for dns_resource_record_source(), dns_resource_record_is_synthetic(), dns_resource_record_signer(), dns_resource_record_is_signer()

resolved: tests for dns_resource_record_to_wire_format()

Note this function does not produce compressed domain names in the RDATA
when serializing the RR.

resolved: tests for dns_resource_record_to_string()

resolved: tests for dns_resource_key_{to,from}_json()

This test doesn't check the generated JSON data in detail, it simply
tests that round-tripping an RR key through the JSON representation
preserves its data.

resolved: tests for dns_resource_record_clamp_ttl()

resolved: tests for dns_resource_record_equal(); LOC records

resolved: tests for dns_resource_record_equal(); SVCB records

resolved: tests for dns_resource_record_equal(); RRSIG records

resolved: tests for dns_resource_record_equal(); NAPTR records

resolved: tests for dns_resource_record_equal(); SRV records

resolved: tests for dns_resource_record_equal(); TXT records