Project structure refactoring.

It's compiling and running some targets!

Store all intellij files in .pants.d/intellij because intellij copies BUILD files to project output folder which was colliding while project generation for a folder because it was just under the same dir.

Changed module names so they won't affect classpath while running.

Fixed scala-reflect bug.

Testing Done:
locally

Reviewed at https://rbcommons.com/s/twitter/r/1002/