Refactor sbus to support futaba's FASSTest26 sbus2 mode (Potentially 36 channels)

[mmosca]

Futaba new T26SZ radio adds support for more than 18 channels by sending an extra SBUS2 frame with sync byte 0x2F before the traditional frame with 0x0F sync byte.

The 2 frames doubles the channel count to to 32 + 2/4 channels. Digital channels seems duplicated, so I will only add 2 digital channels.

The time between frames is ~18-20ms and frame 0x2F is sent first.

Telemetry is triggered after 0x0F packet, as usual.

• Verify changes on scope
• Validate channel distribution
• Test decode logic
• Test sbus2 telemetry
• Test 18 channel sbus/sbus2
• Bump max servos to 34 (blackbox limited to 26, due to 64 bit limit)
• Unbreak blackbox

Demo: https://www.youtube.com/watch?v=jnGiVR0I-ik

[mmosca]

@stronnag did I miss anything on the blackbox side of things?

[stronnag]

@stronnag did I miss anything on the blackbox side of things?

I don't think so.

• BBL headers added with condition
• Conditions in "enabled" switch
• Conditions added to header file.