A Space should be able to get the Email for a User

(User Story, Investigate , Priority: High, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Security, User Interface
Summary: This is particularly useful for lightweight "survey" use cases, where we are passing out shared links, folks are signing up for Querki and then entering themselves into the survey. It's a bit of a UX bug that they wind up typing their email address into both Querki and the Space itself.
There's a real tension here. For security reasons, we absolutely don't want Spaces to be able to just grab the user's email address.
A design to think about: we could add Email as a proper Type. (Really, I've been considering this forever.) A given Email Property could have a flag "Default to User Email Address", or something like that. If set, the UI has a button labeled "Use my Email Address" -- if pressed, it would fill that in. There's still a little bit of user ceremony there, but it's less obviously silly, and makes the process more efficient.
Note that a Space may also want to get the User's Name, but that's already available -- we can get it as _me -> Name. Names aren't considered to be security-privileged as Email addresses are.