Preferred policy hierarchy

From Scratchpad

User-defined preferred policy hierarchies would allow users to conveniently specify priorities for policies.

This extends the AND / OR search mechanism with priorities for policies. With this extension a user can specify to require policy A, B or C but to prefer A over B and B over C.

The extension could also allow to assign a loading to policies in order to give certain policies more weight than others in the search result, even when the policies have been referenced in different filter expressions.