AP_Notify: Create automatic audible lost/crashed vehicle alarm

Feature request

Is your feature request related to a problem? Please describe. When a vehicle crashes or is otherwise lost, it can be difficult to find it if you cannot see it. If you do not have and RC connection, you cannot activate the lost vehicle alarm. The lost vehicle alarm can only be activated by stick gesture or aux switch. If you do not have a GCS connection and GPS, you cannot see its coordinates.

Describe the solution you'd like

• Lost vehicle alarm sound activate and stay activated when the RC and GCS are lost
• Lost vehicle alarm sound activate and stay activated on crash detection
• Change the lost vehicle alarm sound to something more unique, such as the sound of an ELT
• Change RGB lights to flash as bright white as possible and remain flashing after crash detection

Describe alternatives you've considered Pop smoke and launch flares. But probably not practical at this time :)

Platform [X] All [ ] AntennaTracker [ ] Copter [ ] Plane [ ] Rover [ ] Submarine