R32. Allow process-admins to assign valuators to a category

[paarals]

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

Describe the solution you'd like

Mock up

Does this issue could impact on users private data?

Acceptance criteria

• [x] As a process-admin, I can assign valuator(s) to categories
• [x] As a process-admin, I can assign one valuator to different categories

Technical specifications See https://github.com/openpoke/decidim-module-reporting-proposals/issues/25

Implementation

• [X] https://github.com/openpoke/decidim-module-reporting-proposals/issues/25

Testing

1. As a participatory admin, go the participatory space
2. Create a new category and attach any valuator (valuators must be added before that)
3. See the list

Additional context

[paarals]

solved by https://github.com/openpoke/decidim-module-reporting-proposals/pull/28