Support organizing the library via custom tags

[djspacewhale]

Description

Allow for library organization by custom tags. For example, filter and organize the library by "Album Artist"s in addition to "Artist"s.

Problem solved

No response

Other implementations

Album Artists are a default filter in players like Booming Music, and rmpc has a very customizable tabs option.

Benefit

Often, album artists are more useful for library organizing than track artists, and this would allow much more readable organization. My interest is in album artists here, but the implementation should ideally be very flexible for different album tag categories for different use cases.

Duplicates

• I have checked this feature request for duplicates.
• I have checked that this feature is not implemented in the lastest version.
• I have checked the Why Are These Features Missing? page.
• I agree to the Contribution Guidelines.

[OxygenCobalt]

I already factor in album artists within my library creation process. They're just dynamically merged with track artists so you don't have 2 slightly different artist tabs. Can you elaborate more on why you want this fine-grained control? @djspacewhale

[djspacewhale]

It's mostly for classical recordings. See this screenshot, where the recording artists are listed but it's a bit opaque who they performed - as MusicBrainz by convention records composers as album artists and performers as track artists, and I use MB for my music tagging, I'd find some use with that option.