Remove disabled function, optimize and use time() only once

[pipiche38]

• [x] Remove commented line
• [x] Avoid using calling time.time() several time in the same loop. As we don't need a granularity of ms, this should be ok.
• [x] When a device is not seen since 6 hours, set the device to timedout
• [ ] Allow to overwrite the default 6 hours timedout on a device basis with device param "Device_TimeOut"