Rate limiter + improved error mgt + retry limited

Sender flow updated to better manage errors / rate limitations (JSON parse errors)

- Rate limitation added to pro-actively avoid sending too many calls to HUE bridge
- Retry management : added a 'loop stopper' : when 10 retries failed, request fails, no more retries to avoid infinite loops creation
- Error management now manages the 429 error sent back by the bridge (with the 'real' new code the bridge sends back in case of exceeded calls)
- Some clean-up here and there

Author: FredBlo