Added sound signal configuration for the Highest Alarm Level feature

[Limraj]

Description There is a need for the highest alarm level event notification to have a configurable audible signal.

Solution Added "Highest Alarm Level" section to System Settings(old and new ui), where you can configure three sound notification modes, separately for each alarm level:

1. Single notification mode;
2. Continuous notification mode;
3. Disabling the sound signal;