Optionally check quota before media upload
MSC4034 provides more detailed media quota information. This feature is now available in Travis's Matrix Media Repo.
We could optionally check whether we have sufficient quota before attempting to upload new media.
Note: This feature will be important when we create the FOTOs app, and/or when we add support for automatically syncing photo galleries in Circles. In order to not overwhelm the server, we should check for a quota when doing bulk uploads. This gives us a way to prevent unwitting servers being overwhelmed by clueless or greedy users. For example, a free service like matrix.org probably doesn't want to become your free unlimited Google Photos. By only uploading when the server admin has configured a quota, we avoid hurting servers that haven't thought about this possibility.