Detect which bell set is selected in Abel

[drichards2]

There is the potential for reasonable comedy if users have different numbers of bells selected in Abel. Warn if there are inconsistencies.

[jaa46]

Could do a local sanity check easily based on the number of peers, though can't really assume whether it'll be handbell or tower bell ringing. We could send the number of bells in the test messages, possibly alongside more status information like the approximate response time.