PackageManager: use relative module URLs. Refs #2692
PackageManager: Packages module refactor to reduce nested blocks. Refs #2692
PackageManager: use SESSION database. Refs #1092 #2692
PackageManager: removed all absolute URLs, to make the module re-usable. Refs #2692
PackageManager: yumGroupsLoader() method moved to parent module. Refs #2692

Fixes lanaguage selection when no Request object is bound.