RyngDyng App for legacy iOS <= v15.1

The old iOS versions before v15.1 do not well support modern web apps and Apple does not provide support anymore.

In order to support old iPhones etc. with such old iOS versions we have made a freeze of an old RyngDyng app version here:

https://www.archery-electronics.com/static/app_coach_legacy/index.html
This version should also run on e.g. iOS v12.x