Support cumulative voting rendering #200
Description
Due to the recent discovery in our explorer about unsupported voting types, we realized we should give support for the cumulative voting (a type of quadratic voting).
You can see a working election here: https://explorer.vote/process/6b342d99f2187bf87ae56dfceaf3b6531c336365830e460e212d02000000006d/1
Both the results and the envelopes views are broken due to this. Note: as said in vocdoni/explorer#121, we should first ensure we're not doing "default" renderings, to avoid issues in the future. After that, we should add specific support for cumulative votings.
Depends on vocdoni/vocdoni-sdk#408, since we don't have an easy way to identify these type of votings right now.