A module to set on init ztimer->adjust_sleep/adjust_set values.

When this module is active, then on init if no CONFIG_ZTIMER_USEC_ADJUST_% values are set for the BOARD correction values adjust_sleep and adjust_set will be calculated in set for the required clocks.

Note that some BOARDs clocks require a startup time to get accuarate values, a configurable CONFIG_ZTIMER_AUTO_ADJUST_SETTLE value can be set for this.

Alternatively CONFIG_ZTIMER_USEC_ADJUST_% values can be set in the BOARDs configuration header board.h. These can be found out by running tests/sys/ztimer_overhead