Integration tests are now run in temporary directory. Implemented
GradleManager.
Fixed forge-output.xml location issue (it was created in current
directory not project's). Created and implemented GradleProjectCache.
Integration tests seems to be running properly (not implemented yet).
GradleManager now works with profiles.
Moved forge library installing logic from GradleProjectCache to
GradleFacet (now it's just only a cache service).