Support Yaw Alignment in AP_DDS External Localization

[Ryanf55]

Feature request

Is your feature request related to a problem? Please describe.

See align_yaw_to_ahrs in the T265 driver.

Use a momentary switch for VISUALODOM_ALIGN (see RC_Channel.h), which could even be done at startup by Lua.

Describe the solution you'd like

Allow localization (odom) data from cartographer coming in from AP_DDS to allow the EKF to align cartographer yaw to become aligned with the compass yaw in EKF.

Describe alternatives you've considered

Ignore yaw (current behavior)

Platform
[x ] All
[ ] AntennaTracker
[] Copter
[ ] Plane
[ ] Rover
[ ] Submarine

Additional context

Relates to ArduPilot/ardupilot_ros#12