mc_acro_params: beginner/tuning friendly defaults

high rates and (super) expo are necessary for
- acrobatic flying
- fpv
- racing
but they are not useful for:
- a typical vehicle's rate control tuning
- beginners

The defaults that I set in #8036 were put with the assumption Acro mode
is mainly used on racing drones for acrobatic manouvers but instead
users including me use it most of the time to tune any drone.
When tuning the rates are lowered and expo disabled.

My suggested strategy is to make the beginner friendly rates without
expo which are good for tuning the default and document more clearly
how this can be raised for acrobatic flying in documentation and later
on hopefully also directly in the ground station UI
on an Acro mode specific page.

src/modules/mc_rate_control/mc_acro_params.c

@@ -49,7 +49,7 @@
  * @increment 5
  * @group Multicopter Acro Mode
  */
-PARAM_DEFINE_FLOAT(MC_ACRO_R_MAX, 720.0f);
+PARAM_DEFINE_FLOAT(MC_ACRO_R_MAX, 100.f);
 
 /**
  * Acro mode maximum pitch rate
@@ -63,7 +63,7 @@ PARAM_DEFINE_FLOAT(MC_ACRO_R_MAX, 720.0f);
  * @increment 5
  * @group Multicopter Acro Mode
  */
-PARAM_DEFINE_FLOAT(MC_ACRO_P_MAX, 720.0f);
+PARAM_DEFINE_FLOAT(MC_ACRO_P_MAX, 100.f);
 
 /**
  * Acro mode maximum yaw rate
@@ -77,7 +77,7 @@ PARAM_DEFINE_FLOAT(MC_ACRO_P_MAX, 720.0f);
  * @increment 5
  * @group Multicopter Acro Mode
  */
-PARAM_DEFINE_FLOAT(MC_ACRO_Y_MAX, 540.0f);
+PARAM_DEFINE_FLOAT(MC_ACRO_Y_MAX, 100.f);
 
 /**
  * Acro mode roll, pitch expo factor
@@ -92,7 +92,7 @@ PARAM_DEFINE_FLOAT(MC_ACRO_Y_MAX, 540.0f);
  * @decimal 2
  * @group Multicopter Acro Mode
  */
-PARAM_DEFINE_FLOAT(MC_ACRO_EXPO, 0.69f);
+PARAM_DEFINE_FLOAT(MC_ACRO_EXPO, 0.f);
 
 /**
  * Acro mode yaw expo factor
@@ -107,7 +107,7 @@ PARAM_DEFINE_FLOAT(MC_ACRO_EXPO, 0.69f);
  * @decimal 2
  * @group Multicopter Acro Mode
  */
-PARAM_DEFINE_FLOAT(MC_ACRO_EXPO_Y, 0.69f);
+PARAM_DEFINE_FLOAT(MC_ACRO_EXPO_Y, 0.f);
 
 /**
  * Acro mode roll, pitch super expo factor
@@ -123,7 +123,7 @@ PARAM_DEFINE_FLOAT(MC_ACRO_EXPO_Y, 0.69f);
  * @decimal 2
  * @group Multicopter Acro Mode
  */
-PARAM_DEFINE_FLOAT(MC_ACRO_SUPEXPO, 0.7f);
+PARAM_DEFINE_FLOAT(MC_ACRO_SUPEXPO, 0.f);
 
 /**
  * Acro mode yaw super expo factor
@@ -139,4 +139,4 @@ PARAM_DEFINE_FLOAT(MC_ACRO_SUPEXPO, 0.7f);
  * @decimal 2
  * @group Multicopter Acro Mode
  */
-PARAM_DEFINE_FLOAT(MC_ACRO_SUPEXPOY, 0.7f);
+PARAM_DEFINE_FLOAT(MC_ACRO_SUPEXPOY, 0.f);