Email sync setup control for firm admins

The current method for adding mailboxes is inadequate and a little concerning, as it requires setting everyone's privileges to Admin or Owner for an unspecified amount of time, so they can access the Settings menu.

This needs to be controllable by the firm admin - a link that admins can generate and send to users for self-service enrollment would suffice.
Better yet, move the Mailboxes setting into the user preferences settings menu so all can access it; I can't think of many good reasons it needs to be locked away.

Opening permissions floodgates for routine tasks should never be standard practise, it's too faffy and too risky.