I should be able to Edit a Role

Summary:

This story is now just for editing per se. Permission handling has been split out into I should be able to define the Space-wide Permissions for a Role.

Most importantly, though, this should include the ability to edit the default permissions on a Role, to match what we have for Invite Links. Since Invite Links and Custom Roles are mostly the same thing, we should unify their UIs and capabilities.

We might want to scrap the custom UI from Invite Links, and instead use something like the standard Security layout. That's essentially what it is doing, after all -- letting you choose Permissions -- but it's a bit simpler, without all the inheritance. Instead, it's basically just a list of checkboxes of whether this Role confers this Permission. That's very slightly more complex, but more consistent and much more powerful and correct.

This story originally included being able to Delete a Role. That's actually fairly hard, so it has been split out into its own story.