Cleanup build mechanisms for sbt to IDE.

Review by @cunei, @dragos @adriaanm 

Note:  I need to know if this will break the pr-validation before I can merge.  How can we test that?  Also, I need to be the one that clicks merge because I need to update our jenkins jobs at the same time.

Thanks!

CC> @gkossakowski let me know if the documentation in the build files is sufficient to know what's going on now or not.