Remove skeleton modules from core

Because there is no clear/safe way how to uninstall missing module, the removal should be done in 2.x, with clear statement at module's page, that the module must be updated to the latest 1.x version before upgrade into 2.x.

I have added an uninstall code, which makes sure the modules won't be enabled anymore.

Automatically closed - issue fixed for 2 weeks with no activity.