Rotorflight Snapshot 4.2.12-20211212

Snapshot Release

This is a Rotorflight development snapshot for beta-testing.

Changes from 20211122

• Use semver.org versioning with all version numbers

• Accept Betaflight Custom Defaults files

• Fix mixer input initialization to sane values

• Fix Profile change during flight

• Refactor RX MSP messages

• Implement mixer MSP messages