Improved compliance with the config settings `[migrations].ALLOWED_DOMAINS`, `[migrations].BLOCKED_DOMAINS`, and `[migrations].ALLOW_LOCALNETWORKS`, which control the remotes that Forgejo can access for git & LFS migration and mirroring operations, fixing time-of-check vs. time-of-use issue and missing checks in LFS.  git mirror HTTP operations have been adjusted to never follow HTTP redirects in order to ensure that these settings are followed, which will break HTTP mirroring if a redirect is served by the git HTTP remote.