samples: reel_board/mesh_badge: Add protection for fast key presses

It was possible to freeze the application by pressing the user button
too frequently. This was likely due to the stack not keeping up with
the send requests and running out of buffers.

Add rate-limiting to the app, so that at most one message per 500ms
can be sent. Also add a user message if the user presses the button
too many times in rapid succession, and inform the other badges of
this misbehaving user.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
3 files changed