Direct Messaging & Following

### Is Your Feature Request Related to a Problem? _No response_ ### Feature Description 1. I prefer Thunder over all other Lemmy apps, in my opinion, it does everything the best, however, how is it the only one with no direct messaging system implemented. 2. I don't know if this system is in Lemmy, but I wanted to know if we could add a following system or a favourite system, so you can follow certain user's posts and whatnot ### Alternative Solutions _No response_ ### Additional Context _No response_