Recover when the connection is closed via RabbitMQ management plugin

Summary:
Currently, Wearg stops sometimes to process messages.

In such case, the easiest method is to force the connection
to close on server-side. A disconnect on client side doesn't work.

To avoid to check the timer, call ::broker::on_tick again,
recheck the time, we simply ask the bot to reconnect.

Test Plan:
Disconnect from the management plugin.
Check it's connected again.

07:59:31 <Wearg> [DEBUG] Can't get message from queue: a server connection error 320 occurred, message: CONNECTION_FORCED - Closed via management plugin /
                 Trying to reconnect...
07:59:42 <Dereckson> .tcl mq connected
07:59:42 <Wearg> Tcl: 1

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D825