switch-on-connect: Add a new module to allow for hotplugged devices to be used by...

switch-on-connect: Add a new module to allow for hotplugged devices to be used by default.

This module implements a simply policy decision that any newly plugged
in devices should be used.

This is a reasonable approach and paprefs will be updated to allow for
this option to be turned on or off.

This is more or less a stop-gap solution. When priority lists are
implemented in the core, then policy modules may ultimately be
re-engineered to adjust the priority lists rather than doing any of
their own routing per-se.