[feat] send email to admin when redis or mongo disconnects/reconnects

[niftylettuce]

it seems like even when redis disconnects and then the server comes back online, it doesn't retry - so maybe look into testing this locally (if it disconnects it should infinitely retry to connect)

had one instance of this in the past a few months ago

cc @shaunwarman or @shadowgate15 if either of you want to tackle