Manual Search is now sorted by the internal priority

I also moved the internal sorting logic from the DownloadApprovedReports to the DownloadDecisionMaker which make sure the sorting logic is only implemented in one place.

I implemented the priority in the UI by adding a ReleaseWeight, which is nothing more than an index. This avoids us having to preserve the original collection order on the UI.

Also added QualityWeight to allow sorting by quality. This Weight is filled using the Quality Profile, so it honors the profile.
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