feat: subsite user pages

[zeucapua]

trafficstars

Implement subsite user pages, accessible via links similar to their socials. Should be styled to the "Weird" theme.

The user pages are pages like this: https://weird.one/zicklag/wiki-page-example

You can create them from your profile page with the + button here:

Originally posted by @zicklag in https://github.com/muni-town/weird/issues/259#issuecomment-2557268517