[F] DIS-351 List favourites on their own page

[leojpod]

Implementation for DIS-351

Test instructions:

• [ ] Login/create an account
• [ ] Favourites a few things on the platform
• [ ] Click on the top-right menu -> My Activities
• [ ] edit the url to add /collections at the end.

Extra tests:

• [ ] See someone else's profile:
  • [ ] from the previous step: copy the collections ' URL somewhere.
  • [ ] logout and login with another User
  • [ ] paste the URL and go there
  • [ ] see how the header changed from "Your collections" to "[firstname]'s collections

Anything else missing?