improved library scan speeds, added library manager component

-libraries tab now opens a library manager
-choose library directory, manually soft scan and rescan
-batched db queues
-mp3 header-based duration extraction

backend/database/sql/sqlcgen/cover_art.sql.go

@@ -32,6 +32,15 @@ func (q *Queries) CreateCoverArt(ctx context.Context, arg CreateCoverArtParams)
 	return i, err
 }
 
+const deleteAllCoverArt = `-- name: DeleteAllCoverArt :exec
+DELETE FROM cover_art
+`
+
+func (q *Queries) DeleteAllCoverArt(ctx context.Context) error {
+	_, err := q.db.ExecContext(ctx, deleteAllCoverArt)
+	return err
+}
+
 const deleteCoverArt = `-- name: DeleteCoverArt :exec
 DELETE FROM cover_art 
 WHERE id = ?