Standardize image loading throughout the app

[AlvaroBrey]

The app loads images in an inconsistent way. Some parts use Fresco which requires special View subclasses, while other uses coil-kt, which is the current recommended way and much simpler to use. However, even the logic to use Coil (like here) is heavily duplicated and hardcoded everywhere.

I'd propose deprecating the Fresco way and its related methods/classes, and writing some kind of wrapper functions for Coil that just take a User object and handle the authorization, or a similar solution.