[iPods] Set Now Playing theme when docked only (and various other docked request

[superluig164]

My request is to add the ability to choose a unique theme to use only when the device recognizes that it is docked.  I suppose this isn't terribly useful for other players which don't dock, but on iPods, they generally show an album art display when docked.  I'd love for Rockbox to be able to mirror this, so I thought, why couldn't Rockbox just change the Now Playing theme whenever you dock the iPod?  Obviously this would be configurable.

Additionally, at least on my iPod Hi-Fi, my iPod used to display the volume level changing when changed with the remote/buttons.  While the behaviour is still the same now (the device outputs a fixed volume and the Hi-Fi manages it) it's still possible to change the volume on the iPod (which has no effect)  Would it be possible to make Rockbox able to change the docked volume and also reflect when it's being changed by the dock?