Copter: use attitude control base class

[IamPete1]

The base AC_AttitudeControl class implements all the methods from AC_AttitudeControl_Heli and AC_AttitudeControl_Multi so there is no need for the extra level of indirection.

This also changes over AC_CustomControl from AC_AttitudeControl_Multi to AC_AttitudeControl.

If we were to add any new methods to multi or heli attitude control this now requires that a virtual or pure virtual function be added in the base class and then overridden, but we have been following that pattern anyway.

[IamPete1]

Unfortunately, we still need to use the class specific object for the parameters.

I was able to get params working by moving to a var pointer param table with GOBJECTVARPTR. This is the same way we do AP_Motors

[IamPete1]

This is needed because the same default defines are used for PID gains.

[IamPete1]

This is saving a suspicious amount of flash on Durandal:

Binary Name      Text [B]         Data [B]     BSS (B)        Total Flash Change [B] (%)      Flash Free After PR (B)
---------------  ---------------  -----------  -------------  ----------------------------  -------------------------
arducopter-heli  -760 (-0.0433%)  0 (0.0000%)  0 (0.0000%)    -760 (-0.0432%)                                  209552
arduplane        0 (0.0000%)      0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                      223436
arducopter       -564 (-0.0323%)  0 (0.0000%)  -4 (-0.0015%)  -564 (-0.0322%)                                  216048
antennatracker   0 (0.0000%)      0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                      665352
ardurover        0 (0.0000%)      0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                      360032
blimp            0 (0.0000%)      0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                      712112
ardusub          0 (0.0000%)      0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                      422468

Much closer to what I would have expected on other the other builds, this is Pixhawk1-1M:

Binary Name      Text [B]       Data [B]     BSS (B)        Total Flash Change [B] (%)      Flash Free After PR (B)
---------------  -------------  -----------  -------------  ----------------------------  -------------------------
arducopter-heli  12 (+0.0012%)  0 (0.0000%)  -4 (-0.0020%)  12 (+0.0012%)                                     38292
arduplane        0 (0.0000%)    0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                       1[25](https://github.com/ArduPilot/ardupilot/actions/runs/7080162785/job/19267654301?pr=25224#step:10:26)88
arducopter       0 (0.0000%)    0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                       48964
antennatracker   0 (0.0000%)    0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                      [29](https://github.com/ArduPilot/ardupilot/actions/runs/7080162785/job/19267654301?pr=25224#step:10:30)6720
ardurover        0 (0.0000%)    0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                      112148
blimp            0 (0.0000%)    0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                      [31](https://github.com/ArduPilot/ardupilot/actions/runs/7080162785/job/19267654301?pr=25224#step:10:32)8220
ardusub          0 (0.0000%)    0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                      125760

I will run elf diff and see where the saving is coming from.

[IamPete1]

Elf diff here: https://drive.google.com/file/d/1ttP5etMZU84Gjc-8dE6Um4KbaFqQPz8i/view?usp=sharing

All of the changes are in persisting symbols. So no functions are added or lost.

I don't think we have lost any functionality. Its only a saving on 2M boards, so its probably related to the optimization level. I usually put such things down to "alignment".

[IamPete1]

Heli elf-diff, look like the same thing:

https://drive.google.com/file/d/1u0rjDFlPjxEqXVyrg1rTontytBn8WwmB/view?usp=sharing