New MSPv2 VTX Query Message Types

[SumolX]

Allows for devices such as the Flipper Zero HDZ Toolkit to gain insight into the VTX current state.
Cleaned up msp protocol definitions which now match betaflight/inav and place them within a new file called msp_protocol.h
Fixed MSPv2 parsing bug (Did not handle length of zero)

New MSPv2 VTX Message Types:
#define MSP_VTX_GET_MODEL_NAME 0x0384 // Query VTX for name
#define MSP_VTX_GET_FC_VARIANT 0x0385 // Query VTX for flight controller variant
#define MSP_VTX_GET_FW_VERSION 0x0386 // Query VTX for firmware version
#define MSP_VTX_GET_TEMPERATURE 0x0387 // Query VTX for temperature in celcius
#define MSP_VTX_GET_HW_FAULTS 0x0388 // Query VTX for hardware errors

[SumolX]

I am now code complete and the PR is ready for review.