[Feature Request] Show time of last successful message sync

[asavageiv]

I'm often a bit nervous that AirMessage has silently stopped working. It'd be great to have a UI indicator of the last time the app successfully synced messages to the AirMessage server and the last time the server successfully synced messages from iMessage. Knowing these would give confidence things are still working correctly for those of us who don't receive a lot of messages and give an indication of when the server needs to be restarted because something has gone wrong.

P.S. AirMessage is great! Thank you so much!