MPS.Thirdparty: Fixed classloading issue due to wrong packaging

[arimer]

This PR fixes #789

The changes made, are based on the current module properties configuration and packaging of the JAXB module solution.

Changes are

• MPS.Thirdparty is confiured as an intellij plugin with the id "com.intellij"
• stubModelEntry and modelRoot are resolved via the ${platform_lib} path
• Packaging was done the same way it is done for JAXB

Simple Test

• in addition I've added a simple test scenario
• We now have solution that uses some BL classes provided by MPS.Thirdparty
• This solution is part of the test build conflig and should be generated and compiled during CL build
• in case we have classloading issues, its compilation will fail

[arimer]

Dang! I though I added it, but forgot it :/

Now it should be done

[arimer]

I did try it on the branch mentioned here https://github.com/JetBrains/MPS-extensions/issues/789. However I did not take the artifacts from nexus but use the local ones.