As the Owner, I should be able to turn off certain permissions for myself

(User Story, Investigate , Priority: Medium, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Access Control
Summary: The canonical example here is Can Comment, which controls a bunch of UI. It should be possible for me to turn off comments in the Space completely, including for myself, so that I don't waste pixels on it.
This needs to be done with great care! It is very important that the Owner cannot turn off most permissions for hirself, or you could easily break the Space. The implication is that a given permission needs a flag that indicates whether it can be turned off for the Owner.
Not sure what this looks like from a UI POV, or what the flags look like. Maybe we add a special "Nobody" pseudo-User, which if present means even the Owner doesn't have this?
(Really, in the Can Comment case, this probably wants some specific UI gloss over it.)