Store each client's play queue in the database

The queue lived in memory and was shared by all clients, so a restart or a
finished sync cleared it. Every client now has its own queue in the new
queue and queue_song tables (added to the undeployed migration 000006).

The music endpoints return the queue ID in the X-Queue-Id header and expect
it back. A request without an ID, or with an ended one, starts a new queue.
/music/reset ends the queue and returns a new ID, and a sync ends all
running queues. Ended queues are kept as history.

The deprecated legacy routes without the /api/v1 prefix are removed.

internal/db/repository/models.go

@@ -11,6 +11,23 @@ import (
 	"github.com/jackc/pgx/v5/pgtype"
 )
 
+type Queue struct {
+	Uuid                uuid.UUID          `json:"uuid"`
+	CurrentSong         int32              `json:"current_song"`
+	LastFetchedSongUuid uuid.UUID          `json:"last_fetched_song_uuid"`
+	StartedAt           pgtype.Timestamptz `json:"started_at"`
+	EndedAt             pgtype.Timestamptz `json:"ended_at"`
+}
+
+type QueueSong struct {
+	QueueUuid      uuid.UUID          `json:"queue_uuid"`
+	SongNo         int32              `json:"song_no"`
+	SongUuid       uuid.UUID          `json:"song_uuid"`
+	SoundtrackName string             `json:"soundtrack_name"`
+	SongName       string             `json:"song_name"`
+	AddedAt        pgtype.Timestamptz `json:"added_at"`
+}
+
 type Session struct {
 	Token      string             `json:"token"`
 	IpAddress  string             `json:"ip_address"`