Calculate max command frequency off of connection intervals

[qdot]

This is going to require extra features in blteplug, but it'd be nice to calculate our maximum update rate for ble devices based on connection intervals rather than just guessing. We can get this info on Win11 >= 21H2, Android, I think it's queryable in CoreBluetooth, and I'm guessing also available in Bluez, so it's mostly a matter of getting it supported in btleplug.

Filed over on btleplug at https://github.com/deviceplug/btleplug/issues/410