[request] Add ability to turn off RSS feeds

[sneakers-the-rat]

Pitch

Add an option to the 'privacy and reach' menu to be able to turn off RSS feed generation for more private profiles. I think putting this in the same place that someone would also change their approve follows/discoverability settings makes it discoverable enough - if you are going to go make your profile more private, this is one of the levers you can pull.

Should be pretty simple to do :)

Motivation

More control over account privacy