drivers: clock_control: nrf: reimplementation including API updates

Reimplementation of clock control driver for nrf platform. It includes
latest API changes: asynchronous starting and getting clock status.

Additionally, it implements calibration algorithm which optionally
skips calibration based on no temperature change. Internal temperature
sensor is used for that.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>