Integrate PlatformIO `init`

[jonpas]

$ platformio init --ide eclipse --board «board»

Need to figure out how to call above with ProcessBuilder after project has been generated.

var pb = new ProcessBuilder.inheritIO().command("platformio", "init", "--ide", "eclipse", "--board", '''«board»''');
pb.redirectOutput(Redirect.INHERIT);
pb.directory(new File("/home/..."));
pb.start();

Additionally change src_dir to src-gen.