Automate all steps of Maven Central releases

[jplewa]

Description

Right now we perform the final steps of releasing to Maven Central (closing and releasing the repository) manually on the Sonatype website. This was useful initially while we were validating our solution, but now I believe we have enough faith in our release pipeline to approve everything automatically.

Point 7 in this guide shows a plugin that automates the final release steps (closeRepository, releaseRepository, and closeAndReleaseRepository). I don't believe we'll be able to use this exact plugin, but there might be another one or some other way to automate this through gradle. If adapting some ready-made solution isn't possible, there's also the option to use a script like this one.

Related task: #204

Acceptance criteria

• The publishToMavenCentral tasks should incorporate all the steps needed to fully release a package OR extra task should be created to finalize the release.