Add meters climbed data field

[firsara]

I'm pretty new to writing anything for garmin devices, so I didn't quite got this running as a test, perhaps you could include some documentation in a CONTRIBUTING.md file on how to help out.
I love the watch face and have some ideas for new features.

Meters climbed / total elevation would be an amazing indicator alongside a distance display, especially if doing a lot of hiking in the mountains and not necessarily tracking such activities, you'd still get a good picture of how you were doing that day.

That being said, as far as I know the value provided won't take elevation gain from cycling into account.
For such cases something like pinging Sensor.Info.altitude every other minute (perhaps make this configurable via an "accuracy" setting) and accumulating gained meters might be more accurate but probably also a lot more draining on the battery, so for now I'd stick to the data provided by garmin.

The new setting Meters climbed uses the same icon as for altitude, as I think it's quite an appropriate choice.