This service allows to synchronize the clock with the application
server.
Synchronization requests are initiated by the device in a regular
interval, configurable via Kconfig.
The implementation only supports TS003-2.0.0, as the previous revision
TS003-1.0.0 requested to temporarily disable ADR and and set nb_trans
to 1. This causes issues on the server side and is not recommended
anymore.
Signed-off-by: Martin Jäger <martin@libre.solar>