Removes the `distribution:bwc` project in favor of
`distribution:bwc-release-snapshot` and
`distribution:bwc-stable-snapshot`.
`distribution:bwc-release-snapshot` builds a snapshot of the
latest release branch (5.4 now) if needed for backwards
compatibility. `distribution:bwc-stable-snapshot` builds a
snapshot of the latest stable branch (5.x now) if needed for
backwards compatibility.
Some packaging tests depend on snapshot versions of packaging
distributions yet the build does not use a repository that includes such
distributions. While we could add such a repository, a better strategy
is to follow our approach for other BWC tests where we depend on a
locally-compiled archive distribution. This commit adds a local
compilation of packaging artifacts and substitutes these anywhere that
we would otherwise depend on a snapshot of these artifacts.
Relates #24861