R30. A valuator can assign another valuator

[paarals]

Is your feature request related to a problem? Please describe.

Describe the solution you'd like As a valuator I want to be able to assign other valuators.

Additional context

Does this issue could impact on users private data?

Acceptance criteria

• [x] A valuator can assign other EXISTING valuators
• [x] A valuator can remove himself of the proposal, but can't remove other valuators
• [x] A valuator CAN'T create new valuators

Technical specifications (https://github.com/openpoke/decidim-module-reporting-proposals/issues/24)

Implementation https://github.com/openpoke/decidim-module-reporting-proposals/pull/27

Testing

1. As a valuator, go to your assigned proposal
2. In the details of the proposal, add another valuator

[paarals]

closed by https://github.com/openpoke/decidim-module-reporting-proposals/pull/27