Add IDEA and Eclipse project setup instructions

[nykolaslima]

Add instructions about python scripts used to configure the project into IDEA and Eclipse.

[dinowernli]

Thanks for the contribution, but I was in fact about to remove those bash scripts. There is now a bazel plugin for intellij, which I think should support the polyglot project.

So if you want to write that section, I suggest writing a guide on how to setup the intellij plugin :)

[nykolaslima]

Actually i tried setup using the intellij plugin but it didn't work and using the script it worked.