Rewrite score computing
Created by: njoyard
- Remove scores from DB
- Create a ScoredVotes view (vote, [representative, proposal, date], score)
- Rewrite the DossierScores view that aggregates entries from the previous one over dossiers
- Create a Scores view that aggregates entries from the previous one over representatives
- Remove score update facilities everywhere
- Update the API accordingly
Note: include hooks to set up different score aggregation rules (see #63)