Move *_AUDIO_PLUG actions from Intent to android.media.AudioManager

For ACTION_HEADSET_PLUG (already in SDK):
 - duplicated definition in AudioManager and moved
  javadoc there. Javadoc in Intent points to AudioManager.
 - the String value is not changed

For ACTION_HDMI_AUDIO_PLUG (being added in SDK):
 - moved defintion from Intent to AudioManager
 - updated String value to reflect package name "android.media"
  instead of using "android.intent"
 - added definition of the extras, but removed "name".

For ACTION_ANALOG_AUDIO_DOCK_PLUG,
    ACTION_DIGITAL_AUDIO_DOCK_PLUG,
    ACTION_USB_AUDIO_ACCESSORY_PLUG,
    ACTION_USB_AUDIO_DEVICE_PLUG, all hidden:
 - moved definition from Intent to AudioManager,
 - changed the value from "android.intent.*" to "android.media.*"

Updated AudioService, UsbDeviceManager and UsbHostManager
 to refer to the actions in AudioManager, not Intent.

Bug 17289385

Change-Id: I61dd73140022d2bb9a676a57f595092c8fa89dcc