Remove manual RC trim calibration and add FW_ prefix to trim parameters

[sfuhrer]

Solved Problem

With https://github.com/PX4/PX4-Autopilot/pull/22668 we introduce a new way of automatically trimming out a FW vehicle (or a VTOL in FW). This makes the legacy way of trimming a plane manually quite redundant, and thus I propose to remove it here. Also helps to advise for a consistent bring up process: first flight in Stabilized mode --> trims are stored --> also applied in the following manual flights.

Solution

• remove manual RC trimming functionality
• rename TRIM_ROLL/PITCH/YAW-> FW_TRIM_ROLL/PITCH/YAW to make it clear that those are the FW trims

Changelog Entry

For release notes:

Improvement: Remove manual RC trim calibration and add FW_ prefix to trim parameters.

FYI @MaEtUgR @dagar as discussed in the devcall yesterday.

[ryanjAA]

Thanks for thinking of me. We use the control allocator trim field on every aircraft and manually set the wheel trim via pwm min and max (no other way for wheel). We don’t do it from the RC trim copy feature from the RC remote so as long as that isn’t gone 🙏🏻.

[sfuhrer]

Let's check if QGC still uses it (I assume so), and if so then remove it from there first.