move vehicle at rest detection ekf2 -> land_detector

- move vehicle at reset detection ekf2 -> land_detector
 - ekf_unit: reduce init period
   - Fake fusion is when at rest is quite strong and makes the variance reduce rapidly. Reduce the amount of time we wait before checking if the variances are still large enough.
 - ekf_unit: reduce minimum vel/pos variance required after init
   - Fake pos fusion has a low observation noise, making the vel/pos variances reduce quickly.

Co-authored-by:: bresch <brescianimathieu@gmail.com>

src/modules/ekf2/EKF/common.h

@@ -374,9 +374,6 @@ struct parameters {
 	const float auxvel_noise{0.5f};		///< minimum observation noise, uses reported noise if greater (m/s)
 	const float auxvel_gate{5.0f};		///< velocity fusion innovation consistency gate size (STD)
 
-	// control of on-ground movement check
-	float is_moving_scaler{1.0f};		///< gain scaler used to adjust the threshold for the on-ground movement detection. Larger values make the test less sensitive.
-
 	// compute synthetic magnetomter Z value if possible
 	int32_t synthesize_mag_z{0};
 	int32_t check_mag_strength{0};