After this diff, we have two ways of joining a thread - a general method and a thin-thread specific. It is unfortunate, but we don't have a good way of dealing with it without significant changes to the invite links protocol. The problem with invite links is that we don't have a RawThreadInfo available when joining. We could return it from the server, but it probably isn't worth it. So from now on, we should use the general method useJoinThread wherever possible and a specific useJoinKeyserverThread only when necessary.

For some reason, this component tried to handle thick threads, while being thin thread specific - there are no communities in the thick thread domain. We can simplify the code by calling the thin thread method.

We're moving this method to avoid an import cycle.

We moved the responsibility of creating the query here to avoid repeating the code in all the callers.

We have to accept this as a parameter because selectors that provide it are platform-specific.

This is used in three places:

1. Invite links
2. Auto joining communities
3. Community list

Each of these is for thin threads only