Add Pants Target Type to depmap so that intellij plugin can use this to identify scala target VS java target

Testing Done:
Manually ran
1. ./pants goal test tests/python/pants_test/tasks:depmap
2. ./pants goal test tests/python/pants_test/tasks:depmap_integration

Ci here https://travis-ci.org/pantsbuild/pants/builds/41554780

Bugs closed: 655

Reviewed at https://rbcommons.com/s/twitter/r/1366/
Sync of https://github.com/pantsbuild/pants/commit/8c92f524c5a1ac967b2f2801ed83df30d256ce61