add query of project roles

[sudan45]

Addresses:

• https://github.com/the-deep/server/issues/1485

  This PR doesn't introduce any:

• [ ] temporary files, auto-generated files or secret keys

• [ ] n+1 queries

• [ ] flake8 issues

• [ ] print

• [ ] typos

• [ ] unwanted comments

This PR contains valid:

• [ ] tests
• [ ] permission checks (tests here too)
• [ ] translations