Remove Post Status

## Is your feature request related to a problem?
There is a feature that allows end-users to optionally select a statys for their forum thread. This might be have been a good feature in the past, but this is an extra step that doesn't appear to offer any true value to any stakeholder. It's more work, barely changes anything, doesn't help to create/resolve conversations, and so on.

## Describe the solution you'd like
Unless we can get someone to provide a current use case for this feature, we should remove it and all related code/schema that supports it.

## Describe alternatives you've considered
None at this time.

## Additional context
Unlike the post icon mentioned in issue #160 , this one might have other uses and/or actually be in use. For example, this infrastructure could help us build out a related feature that helps to form a new feature. For example, this could be something that might be used to change how the forums function in a future release. For example, imagine having a StackOverflow kind of option that completely changed how the forums work in the UI, but the API, DB, etc. are all the same. The functional difference would primarily be in the UI.