Add nice markdown documentation for how to use mvn2nix plugin and the buildMaven function within nixpkgs. Update doc/languages-frameworks/maven.md Co-authored-by: Robert Hensing <roberth@users.noreply.github.com> Apply suggestions from code review Co-authored-by: Doron Behar <doron.behar@gmail.com> Apply suggestions from code review Co-authored-by: Doron Behar <doron.behar@gmail.com> Apply suggestions from code review Co-authored-by: Doron Behar <doron.behar@gmail.com>