Betaflight with IDLE ON mode

Based on 2.3.5 + some commits for coming 2.4.0

The Lux target may not connect to CFC, use 2.3.4 then.

CLI and blackbox download are faster - use developer version of configurator to avoid odd behaviour in CLI:
https://github.com/cleanflight/cleanflight-configurator

See older release notes for functionality.