[Feature request] User tagging system

[folkemat]

Just an idea that came to my mind. The aim is to be able to define a specific tag for a specific user, which will be displayed as [text] after the author of a comment, just like the [blocked] tag. RES has/had a similar feature. Useful if you want to remember something about a user.

Implementation: We could use the friend system. This was replaced by the follower system anyway and has therefore become pretty useless. But it is useful to get a list of users. Adding a user as a friend and getting a list of friends is supported by the API. We just have to define a specific tag for a specific friend and save it.