Java Renderers (code generators for Java only sbt projects)

[arixmkii]

Java Renderers coming in 2 flavors - with static field and with simple singleton class. Java code requires Java version 1.8. Code was formatted with Google java format.

Additionally I changed ScalaCaseObjectRenderer to public from package private, because I see no reasons why it should be package private.

Scala code was formatted with some scalafmt config I used for different project, because no default scalafmt was found in the repo.

No tests, because I'm not familiar how to write tests for SBT plugins.

[eed3si9n]

Thanks for the contribution. Testing is documented here https://www.scala-sbt.org/1.x/docs/Testing-sbt-plugins.html.
See also some of the examples here - https://github.com/sbt/sbt-buildinfo/tree/master/src/sbt-test/sbt-buildinfo

[arixmkii]

Thank you for the links! They were really helpful. I added tests for both renderers. Mostly a copy from your ScalaCaseClassRenderer, but with Scala specific parts removed.

[arixmkii]

Increased stack for tests (because it was what made them pass on my machine), but it is a separate commit if someone wants to take a look at the stack issue in details.