Cannot configure app via Gadgetbridge

See https://github.com/Freeyourgadget/Gadgetbridge/issues/1015

The solution might be to port the config to `clay` so that no website is needed to configure it at all (which would be nice anyway), or there may be additional problems related to the difference between how appcomm messages messages work on Gadgetbridge.

I'll give this a try when I get a chance.