Move communities.json under for/

This way we don't have to set the username in a cookie. Should've done
this before.
Stop setting username in cookie

Previous commit removed the need for this. This goes back to what it was
before we changed it. However, ; is still not allowed in usernames, just
in case we want to come back to this later.
Bump version to 8.2.7
Bump version to 8.2.7-dev