#2 CCD bottleneck: `Symphonia` partial tagging

[hinto-janai]

What

Symphonia doesn't have a partial-metadata API. It always reads all the data from a file.

AKA, the Picture data gets allocated into an owned Vec<u8> for every single file...!

This is obviously not ideal, we only need the Picture data once per Album.

Todo

Reach into the internals, add optional allocations.

This section of "The Loop" (the metadata phase) is the 2nd biggest (user time) bottleneck after https://github.com/hinto-janai/festival/issues/13.

Although, it only accounts for 0.3~ seconds in a 2.5 second Collection reset.