- move hw_conf.h file to targets/TARGET_STM/TARGET_STM32WB directory as
this is used also out of BLE feature.
- create a dedicated hal_deepsleep function as the behavior in WB is a lot
different from other existing STM32 targets
- update clock tree configuration to directly clock the entire tree @ 32MHz
out of HSE. This is needed as we want to let the M0 core running without
any change on M0-side of clocks when M4 enters /exits deep sleep.