Expand participatory process status types

The current status types are Unanswered/Accepted/Evaluating/Rejected. I propose a feature where the amount, name and color of status which can by attributed to a proposal can be set in the backend (i.e. in the proposal settings). This can be helpful in a participatory process where ideas "branch off", i.e. where different actors start dealing with the proposals.

Funding might be available in Zürich, if this isn't already a planned feature by somebody else.