The HRTIM still lacks some functions needed for a fine management of the PWM generation. This PR adds several functions. 

Deadtime management
The deadtime can now be managed separately from the rising and falling edges.

Phase shifting
The phase of the second leg can now be updated dynamicall

Bug fixes: 
Readable Independent mode
The independent mode can now be set as buck or boost instead of true or false, making it more readable.

Extra features: 
There is now a board version support for the SPIN board

Ayoub Farah Hassan authored Jul 13, 2022 and Clément Foucher committed Jul 13, 2022

Rewrote hrtim driver with LL APIs. Added Up-down mode (center aligned PWM) for buck, boost and independent mode. Corrected initialization errors for independent mode.

Add capability for finer configuration of HRTIM ADC event generation; Separate event generation postscaler.

Add ability to set discontinuous mode on ADCs; Add support for various trigger sources from HRTIM to ADCs.

New device tree organization, not based on Nucleo dts.

Update error codes.

Update NGND drive to use new Zephyr GPIO API.

Align device tree defines to ***_DEVICE nomenclature.

Integrate data conversion into the data acquisition module.

Add a link to the Wiki in owntech.ini so that information on how to use the libraries is directly accessible.

Use a more generic configuration for DMA.
Corrected error codes.

- Use various DMA 1 channels for ADC data copy instead of ADC 1 and ADC 2;
- Remove asynchronous data dispatch task in favor of a dispatch within the DMA interrupt;
- Clarify ADC functions purpose;
- Add error codes for Data Acquisition functions;
- Properly commented module headers;
- Made some ADC configuration available to user;
- Allow fine channel configuration for each adc;
- Per-channel data acquisition functions return buffers instead of FIFOs.

- Quick (and dirty) fix to replace deprecated `CONFIG_CLOCK_STM32_APB2_PRESCALER` symbol;
- Replace deprecated `device_pm_control_nop` macro by `NULL`;
- Remove NEWLIB config that causes compilation errors (multiple definition of mutex-related functions included by kernel.h);
- Update NGND driver to use Zephyr's new GPIO device tree interface.