Publishing to maven repository other than central

[chikei]

It used to be done through SonatypePublisher with stagingRelease = false and can publish without gpg signing.

Now we're deprecating SonatypePublisher, maybe we can make a MavenPublishModule which work just like SonatypeCentralPublishModule but instead of doing staging in publishAll#publishReleases, we just do the same as in publishSnapshot (i.e. publish to given uri using aether)?

After this we probably can deprecate contrib.Artifactory as well.

[lihaoyi]

@lefou tagging you here and in #5464 to resolve these. I think we have most of the code in place, and what is needed is probably updated docs that explicitly cover how to cover these non-maven-central use cases. Not sure if we'll need any actual code changes.

[chikei]

#5601 (comment) explains what changes in the PR, basically we need a way to 1. instead of using repo1 staging flow, upload directly with aether (the worker.publishToRemote call in current publishSnapshot) in publishing release version. 2. call publishAll without gpg (or a dummy gpg args that does not trigger errors). But otherwise I don't think we need any changes