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.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1756540 13f79535-47bb-0310-9956-ffa450edef68