Rename the previously undocumented HTTPProtocol directive

Rename the previously undocumented HTTPProtocol directive
to EnforceHTTPProtocol, and invert the default behavior
to strictly observe RFC 7230 unless otherwise configured.
And Document This.

The relaxation option is renamed 'Unsafe'. 'Strict' is no
longer case sensitive. 'min=0.9|1.0' is now the verbose
'Allow0.9' or 'Require1.0' case-insenstive grammer. The
exclusivity tests have been modified to detect conflicts.

The 'strict,log' option failed to enforce strict conformance,
and has been removed. Unsafe, informational logging is possible
in any loadable module, after the request data is unsafely
accepted.

This triggers a group of failures in t/apache/headers.t as
expected since those patterns violated RFC 7230 section 3.2.4.
Submitted by: wrowe
Backport: r1756540

Correct AP_HTTP_CONFORMANCE_ flags
Submitted by: wrowe
Backport: r1756555

Renaming this directive to HttpProtocolOptions after discussion on dev@
Submitted by: wrowe
Backport: r1756649

Perform correct, strict parsing of the request line, handling the
http protocol tag, url and method appropriately, and attempting
to extract values even in the presence of unusual whitespace in
keeping with section 3.5, prior to responding with whatever
error reply is needed. Conforms to RFC7230 in all respects,
the section 3.5 optional behavior can be disabled by the user
with a new HttpProtocolOptions StrictWhitespace flag. In all
cases, the_request is regenerated from the parsed components
with exactly two space characters.

Shift sf's 'strict' method check from the Strict behavior because
it violates forward proxy logic, adding a new RegisteredMethods
flag, as it will certainly be useful to some.
Submitted by: wrowe
Backport: r1756729

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x-merge-http-strict@1769662 13f79535-47bb-0310-9956-ffa450edef68