Add target KAKUTEF4V23. Support for M5 and M6 outputs.

[marianomd]

The Kakute V2.3 is almost identical to V2, but introduces two additional motor outputs: M5 and M6.

Tested and working: 2 servo outputs on quadcopter. I had to remove servo output on PA2 for MC because it would shift the fourth motor to M5 when adding a servo. Remaining to test on FW and hexacopter setups.

[DzikuVx]

@marianomd could you please resolve conflicts? Thanks

[marianomd]

Done!