Generic Zigbee siren

[gabriele]

[Beta] Generic Zigbee siren driver

I've created a generic zigbee siren driver that should support all capabilities by Zigbee specifications. Please note that most of zigbee sirens support just a small subset of them, so IE changing siren volume or strobe light doesn't have any effect. It exposes also a Speech Synthesis capability so it's possible to use different configurations depending where it's used (example Warning WarningMode=1 UseStrobe=1 SirenLevel=2 WarningDuration=20 )