Add configurable bundle ID mappings for App Volumes

In BGMBackgroundMusicDevice::ResponsibleBundleIDsOf, we map the bundle IDs of some common apps to the bundle IDs of the processes they use to play audio. See #42 for details.

It would be nice to make this map configurable at runtime so users can add their own fixes for apps that don't work with App Volumes because their bundle IDs don't match the bundle IDs of their CoreAudio clients (i.e. the bundle IDs BGMDriver sees). We could add something to the UI for this, but a configuration file or something like that would be fine as well.

We should also have BGMApp log the bundle IDs of apps when you change their volumes and BGMDriver log the bundles IDs of clients when they start IO. They're currently logged in debug builds, but not in release builds. That way users can check the logs to figure out which bundle IDs to use.