Improved Magnetometer / Compass Bias Estimator (#12998)

Improved Magnetometer / Compass Bias Estimator (#12998)

* Rebased on master and clean-up (untested), this is still the initial method

* Included math.h in compass.c, so checks don't fail

* Change comments, compass is still only running at 167 Hz, not worth investing more

* Alternative method, using only mag data

* Removed unnecessary scaling and fine tuning

* Corrected comment

* Removed no longer needed debug DEBUG_MAG_TASK_RATE, comments and corrected some typos

* Improved readability and update of comment

* Rebased on master and resolved conflicts

* Included math.h and maths.h so checks don't fail

* Update src/main/sensors/compass.c

Co-authored-by: Mark Haslinghuis <mark@numloq.nl>
* Update src/main/sensors/compass.h

Co-authored-by: Mark Haslinghuis <mark@numloq.nl>
* Update src/main/sensors/compass.c

Co-authored-by: Petr Ledvina <ledvinap@gmail.com>
* Changes according to PR comments

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Co-authored-by: Mark Haslinghuis <mark@numloq.nl>
Co-authored-by: Petr Ledvina <ledvinap@gmail.com>