CORE/FIX: Thread Spaces are a major hack and brittle

[janaka]

Thread spaces don't have a concrete relationship with a thread. That results in very brittle logic around getting and creating thread spaces.

This needs a refactor adding a concrete space_id reference to a thread. Threads need to know about a space attached to them. Spaces do not need to know about the thread attached to them.

[janaka]

@osala-eng the thread space logic is really brittle. Honestly, it's terrible. Do you remember the reasoning for going with this setup. Basically not having a proper database reference from thread to space_id is the issue afaik. I've got a fix on the hack which solve one issue not the file upload is broken.