runtime(compiler): include a Java Maven compiler plugin

runtime(compiler): include a Java Maven compiler plugin

@Konfekt suggested adding this [1]; I confirmed that both source
repositories have permissive licenses [2], [3] that permit copying the
code (at least where the compiler scripts are concerned).

[1]: https://github.com/benknoble/Dotfiles/commit/570b1006fd794b0b9f5434b4fed4c2d785fcb05c
[2]: https://github.com/JalaiAmitahl/maven-compiler.vim
[3]: https://github.com/mikelue/vim-maven-plugin/issues/13

closes: #16041

Signed-off-by: D. Ben Knoble <ben.knoble+github@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>