Don't create runnable platform jars anymore, since all they really do is increase build time. Also fix texts and Gradle deprecations. Also also publish common with its shadowed configuration, not the plain java components.
* Make use of `TYPESAFE_PROJECT_ACCESSORS` and `VERSION_CATALOGS` Gradle feature previews to clean up build scripts
* Bump setup-java action to v2, specify AdoptOpenJDK distribution
This has been tested on the following:
- AdoptOpenJDK Java 1.8.0_282
- GraalVM CE 21.0.0 OpenJDK 11.0.10
- AdoptOpenJDK Java 15.0.2
- AdoptOpenJDK Java 16 (also tested with BungeeCord b1556)
- Amazon Corretto OpenJDK 16.0.0.36.1
... with Waterfall b406 on Linux 5.10.28.