Describe the feature

I'd like to be able to filter the playlists list

Why would this be useful to add?

As described in #3440, it's sometimes hard, to find a playlist since they are sorted in no particularly obvious manner.

Concept(s)

This would usually be implemented as some kind of text/search input, that might or might not be directly tied to the playlists list (as one component so to speak)

Additional context

• Similar to Filtering videos in Playlists #1466, but instead of the videos within, the whole playlist should be filterable
• Could be implemented alongside with Add to multiple playlists #1486

This would be useful in two places:

• At /playlist
• The dropdown/select when adding a video to a playlist

Acknowledgements

• I have searched the existing issues and this is NOT a duplicate or related to another open issue.
• I have written a short but informative title.
• I filled out all of the requested information in this form.