Handle different Nuki states

[TeresaRoberts]

If the bridge is unreachable, return the Nuki state undefined, rather than the cached value. If the Nuki state is undefined or uncalibrated, return homekit state of unknown. If the Nuki state is motor blocked, return homekit state of jammed. If the Nuki state is locked, return homekit state of secured. Otherwise return homekit state of unsecured.