git-debpush: Support forcing individual checks

git-debpush: Support forcing individual checks

While using git-debpush interactively, if the user sees that checks
have failed which they know to be safe to override, they typically
just use --force or -f.

However, it is useful for scripts to be able to skip single checks,
and if the user knows that a check will fail in advance of running
git-debpush, it is convenient to be able to specify that but still see
whether other checks fail, where those failures were unexpected.  This
can avoid the user having to run git-debpush more than once.

The list of any checks which failed but were overridden is not stored
in the generated tag.  git-debpush's checks are for the convenience of
the local user only, and the list of failed but overridden checks is
not considered to be metadata for the upload.  Not recording failed
but overridden checks in the git tag keeps git-debpush's checking
independent of its wrapping of git-tag and git-push, which makes
git-debpush simpler and easier to understand.  The complexity is on
the server side, in tag2upload.

git-debpush(1): We want the list of checks that can be overridden to
be at the bottom of the list of options because most users will not
need to look at it.  We also want the description of --force|-f to be
adjacent to the description of --force=<check>.  So move the
description of --force|-f to the end of the list of options.

Signed-off-by: Sean Whitton <spwhitton@spwhitton.name>
Closes: #932459