Closes#5450
- No longer provide the edit route a model when transitioning from the
posts list/content screen and no longer check to see if a copy of the
post already exists in the store from the model hook.
fixes#5136
- wrap notification fetch with a user role check to remove console error
- move author transition down to local route for users/user so that there's no infinite loop
- replace all store calls to fetch the current user with the session user instead
