Persisting setDeviceVolumeBehavior calls

This change does the following
0. Robustly enforce setDeviceVolumeBehavior.
Prior to this change, setDeviceVolumeBehavior could have been overridden
in cases like HDMI_CEC enable/disable, HDMI re-plug, etc.

1. Persist setDeviceVolumeBehavior across AudioService restarts and
system reboots.
Prior to this change, setDeviceVolumeBehavior was lost on AudioService
crash/restart, or system restart.

2. Persist software volume across reboots.
Prior to this change, HDMI_OUT device was initialized as a "Fixed"
Volume device and then updated to either full volume device or
"variable" volume device based on the outcome of HDMI-Sink's CEC
capabilities. However, when connected to a non-CEC capable sink this
would result in audio resetting to 100% on each reboot.

3. Some refactoring around how mFixedVolumeDevices and
mFullVolumeDevices are updated in some instances.

Bug: 153193369
Bug: 155482023
Test: Locally on ADT3
Change-Id: I4adb38c64fe1ae7713992ab83acbd66bce4524a4