Introducing support for Garmin Connect IQ devices

[marccardinal]

This has been tested on various versions of the Garmin Fenix 3 and Fenix 5 watches. I also submitted a companion watch app to the ConnectIQ store: https://apps.garmin.com/en-US/apps/07a231a9-3f2f-4762-b0bb-b8a0b5594f40.

Let me know if you have any questions or need any clarification!