Admin Refresh v3

[limegorilla]

This Issue is in place to convert the AdminUI to a cleaner and better system using NextJS nested routes.

Here's the plan!

/ {...} # App files
  admin /
    new # Adds a new client (office isn't known when you do this)
    [office_id] /
        index # Each office will have a dashboard used to see general info
        [client_id] # Each client has it's own settings page