- fixes #8436

Reduce max yaw error when not using global frame aiding data to prevent large yaw yaw changes after takeoff.

When the EKF is not fusing in observations from the NE global reference frame, the tolerance to yaw errors is much higher. This changes will prevent false triggering of the preflight fail check when operating indoors without GPS where mag field errors can be high.

The define should not be used, as it might be wrong.
This is the case on fmu-v5, which meant that the used RAM was always 1.

https://github.com/PX4-NuttX/nuttx/pull/7

Before that, different modules (ekf2, commander & land detector) changed
params upon different events:
- ekf2 & commander set params after disarm
- land detector set params on land detected
If the 2 events were several 100ms appart, it led to 2 param saves, and
the latter param set could have been blocked by an ongoing save. And if
the land detector was blocked, it could lead to mag timeouts.

This patch makes all modules use the same event, thus only a single param
save will happen.

If we want to have guarantees to never block, we should introduce a
param_try_set() API method.

_should_stop_file_log is set after disarming: logging continues for 1s
to measure the CPU usage.
During that time, other modules might change params (such as ekf), and
we don't need to have these the log. However currently all modules do
not notify the system when setting params after disarming.
Meaning this patch is not strictly needed, it's more a preventive
measure.

This fixes a bug preventing use of auto and RTL when taking off with GPS.

The EKF origin height is calculated to be where the vehicle was at takeoff and is suitable as a surrogate home altitude.

If we have taken off without GPS and gained it in flight, the home vertical position can be set, but not the horizontal.

This enables the reference height to be reset when global vertical position becomes available in-flight.

 - check format first to reduce build utilization

This branch fixes a reported bug, fixes tow potential bugs and fixes a minor documentation error.

1) Removes code un-used under normal conditions that would prevent a height reset if a negative height variance was present. Potential bug.
2) Fix error in parameter documentation.
3) Adds missing initialisations for class variables . Potential bug.
4) Prevents the EKF loss of navigation message being output on startup. Reported bug.

Required for Optical Flow on the Aero via RTPS

Previously, the only way to clear a failed nav test was to reboot. This hindered testing.

This check is performed for up to 30 seconds after takeoff or until  a horizontal speed of 5 m/s has been achieved.
If the vehicle is not landed and the check is active, then the yaw will be declared as failed if the velocity innovations fail for a continuous period of 1 second.
This will cause the local and global position and velocity validity to be latched false to prevent unsafe use of position control modes.

Fix the bug allowing arming without GPS checks passed in the first 20 seconds after gaining GPS lock when COM_ARM_WO_GPS is set to 0
Allow 10 seconds after boot for EKF quality checks to pass before reporting failure to allow EKF to stabilise.
Move GPS quality checking and reporting to after all innovation and bias checks.
Make messages more informative.
Add missing GPS speed accuracy check.