cd19564acc
This is, in large part, a refactoring: we rename `CommitVerification` to `ObjectVerification`, and adjust `ParseObjectWithSignature` (previously `ParseCommitWithSignature`) to work on an object, rather than a commit. This in turn, lets us implement `ParseTagWithSignature` on top of it, so commit & tag signature verification will share most of the code. Work sponsored by @glts. Signed-off-by: Gergely Nagy <forgejo@gergo.csillger.hu>