Memory leak due to duplicated lang libraries in Project API package cache

[azinneera]

Description:
Lang libraries that are not imported by default are being duplicated in the Project API package cache after the first compilation when triggered by the LS. This happens when the version of the lang library is unknown. When the version is unknown, we always resolve it from the repository and add it to the package cache resulting in duplication.

Affected Versions:
At least SL Alpha 5