Add support for China

[matin]

Garth natively supports China.

You just have to do the following in GarminConnect:

self.client.configure(domain='garmin.cn')

For reference:

• https://github.com/yihong0618/running_page
• https://github.com/cyberjunky/python-garminconnect

[longstone]

This should be set by configuration or default? My Understanding would be that it's configurated?

[matin]

Configuration