Merge r1891497, r1906480, r1906482, r1906501, r1907235, r1907235, r1907236, r1907237...

Merge r1891497, r1906480, r1906482, r1906501, r1907235, r1907235, r1907236, r1907237, r1907506, r1907506, r1907670, r1907960 from trunk:

* Allow to load /home/travis/build/apache/httpd/.gdbinit

Prep for GitHub actions: move CPAN handling into test scripts,
don't reference /home/travis directly.

Enable simplest CI test cases in GitHub Actions (currently also
still enabled in Travis).  Based on apr/trunk.

Limit triggering on non-code changes, try to capture error_log as
an artifact on failure.

Migrate more tests to Github Actions.

Github: fixes #340, fixes #339

Migrate more tests to Github Actions.

Github: fixes #340, fixes #339

Travis RIP, WIP.

Add todo list for GHA migration.

Further migration of tests to GHA, though HTTP/2, ACME and
i386 build testing are all failing so currently disabled.
Caching needs adjusting to use a different model to Travis.

Further migration of tests to GHA, though HTTP/2, ACME and
i386 build testing are all failing so currently disabled.
Caching needs adjusting to use a different model to Travis.

Clear cache for mod_tls test.

Also run CI for PRs against 2.4.x.

Submitted by: rpluem, jorton

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1907961 13f79535-47bb-0310-9956-ffa450edef68