[Bug Report] No `User.display_name` with Non-Client API

[DerKO9]

Related Problem/Issue
Similar to how you can format song file names, I'd like to be able to format playlist file names. I like to add the prefix "Zotify_" to my playlist file names to show that they come from Zotify and are a "read-only" playlist when I import them into my music server. I would also like to include owner in the m3u8 file name so two playlists that share a name but have different owners will not have conflict.

Ideal Solution
There would be a new config option called "OUTPUT_M3U8" which would be a string that has placeholders. The default value would be "{playlist_name}" and placeholder values would be:

• playlist name
• playlist id
• owner display name
• owner id

If I had the string "Zotify_{owner_display_name}_{name}" and tried downloading my playlist called "Blues", the output would be Zotify_Derko_Blues.m3u8. If my friend "Steve" also had a playlist called "Blues" and wanted to add it to my music server, there would not be an issue because his playlist will be named Zotify_Steve_Blues.m3u8 and my own "Blues" playlist file will not be overwritten now that the owner is apart of the file name.

Additional context
I have a pull request to get this one started #207. I was able to implement 3 out of the 4 placeholders I want.

[Googolplexed0]

User.id == User.display_name if not permit_client_api() due to metadata responses not returning the display name information. Unclear if there is a way to get this information.

[DerKO9]

Unclear if there is a way to get this information.

One idea I was working on earlier was to try to implement this "get_user_profile" function in librespot-python. I made a PR in your fork of it Googolplexed0/librespot-python#2 This function is present in the Rust and Java implementations so i figured i would recreate it in Python as close as i can.

Maybe we can use this function to get the display name from the user id. I was working on this idea here (#213) to try to make that happen but im unsure if this is the best way to get the display names. It uses a lookup table to store display names already found so it doesnt make more requests than needed. I have tested it locally on a couple playlists with different owners and was able to get the output playlist file to show their display names instead of their user ids