add barometer altitude to crsf telemetry

[her01n]

Add barometer altitude to CRSF telemetry.
Altitude is already served in GPS frame, the separate frame has the advantages:

• works with barometer only, without GPS
• has dm fidelity instead of m for GPS

[mmosca]

The baro sensor was added before and reverted in #9858 due to #9761 so it needs testing to make sure it does not cause VSpd to break on edgetx.

[her01n]

I have considered compability with older tx versions.
Patch #9858 sends both vertical speed and altitude in the same frame 9.
This one sends keeps vertical speed in frame 7 and sends only the altitude in frame 9.

Support for vertical speed frame 7 was added in edgetx 2.3, support for vertical speed in frame 9 was implemented in 2.8.0.
The regression was therefore present in edgetx versions 2.3 - 2.8.0.
I have tested with edgetx 2.5.0 and the vertical speed was working as expected.

Hence i believe this improvement causes no regression in vertical speed telemetry.