* tests: Added a regression test for generic_cartesian kinematics
* kinematics: An intial implementation of generic_cartesian kinematics
* generic_cartesian: Refactored kinematics configuration API
* generic_cartesian: Use stepper instead of kinematic_stepper in configs
* generic_cartesian: Added SET_STEPPER_KINEMATICS command
* generic_cartesian: Fixed parsing of section names
* docs: Generic Caretsian kinematics documentation and config samples
* generic_cartesian: Implemented multi-mcu homing validation
* generic_cartesian: Fixed typos in docs, minor fixes
* generic_cartesian: Renamed `kinematics` option to `carriages`
* generic_cartesian: Moved kinematic_stepper.py file
* idex_modes: Internal refactoring of handling dual carriages
* stepper: Refactored the code to not store a reference to config object
* config: Updated example-generic-cartesian config
* generic_cartesian: Restricted SET_STEPPER_CARRIAGES and exported status
* idex_modes: Fixed handling stepper kinematics with input shaper enabled
* config: Updated configs and tests for SET_DUAL_CARRIAGE new params
* generic_cartesian: Avoid inheritance in the added classes
Signed-off-by: Dmitry Butyugin <dmbutyugin@google.com>