Miscellaneous UI/UX improvements (preview, do not merge)

A bunch of CSS tweaks and a couple features (descriptions in commit messages). I will attach screenshots for these and will split these up based on what everyone can agree on.

Goals:
* add more whitespace around text, which is pretty cramped in places.
* remove a UX annoyance (autocomplete when adding user)
* make non-links not look like links
* show admins system email of users without having to navigate to edit settings