Add storage space warnings i.e. "X is almost full" to user notification settings

Add storage space warnings i.e. "X is almost full" to user notification settings: Users in general don't like notifications about something they can do nothing about. Repeatedly being told some huge data store is now almost full is an annoying message to repeatedly be given. In the first place 90% of e.g. 200TB leaves quite a bit of head room and secondly almost nobody in a multi-user setup has the authority and/or tech skills to change the situation. Storage space notifications should be treated like other notifications and in control of the admin and end user, both whether or not...