PackageCandidates now implements the full CoreResource
PackageCandidates now implements the full CoreResource

This means that with a bit of luck we should now be able to use documentation
and build reports with candidates.

Also got rid of the last withXXX from Candidates.


edsko/hackage-server,chrisdotcode/hackage-server,agrafix/hackage-server,haskell-infra/hackage-server,tkvogt/hackage-server,agrafix/hackage-server,ocharles/hackage-server,edsko/hackage-server,tkvogt/hackage-server,grayjay/hackage-server,erantapaa/hackage-server,chrisdotcode/hackage-server,erantapaa/hackage-server,dzackgarza/hackage-server,snoyberg/hackage-server,grayjay/hackage-server,ocharles/hackage-server,dzackgarza/hackage-server,snoyberg/hackage-server