Offline packaged packages should have precedence over online fetched packages if same version number ("hybrid installer")

Currently online packages are downloaded from the servers even if a package with identical name and version is already packaged within the installer. "packagemanagercore_p.cpp" defines PackageSource from "resource:" with priority 0 whereas online sources have priority 1.

It would be more practical if packages with same identifiers and versions from both online and offline repository would only be installed from the offline source and not downloaded from the online source.