This properly separates the forge and fabric mixins in the merged -mod jar.
By some miracle Forge was 'working' with the Fabric mixins, but this is probably safer overall.
* Update so many dependencies, merge Forge/Fabric for final
* Clean up contrib docs for Gradle change
* Fix setting compat flags while using toolchain
* Fix deprecation in doc printer
* Restore proper forge JAR name
* Add dist classifier for mod jar
* Properly relocate new bStats
* Fix jar used from fabric
* Fix fabric bom
* Dup the shaded classes for consistency
* Sync Forge/Fabric log4j versions, de-dup
* Downgrade both log4j. This will work
* Update some plugins as well
* Drop the fabric force stuff
* Use duplicate strategy to directly merge jar