run_device_action dispatched play, pause, stop, next/previous track,
set_volume:N and toggle_mute by string and returned
{success, action, message} instead of the DeviceActionResultDict its
contract names. The typed methods it called (play(), set_volume(), ...)
are the interface; napalm-device-types deprecates run_device_action.
BREAKING CHANGE: run_device_action is removed.
Closes#3