Listenbrainz scrobbling (#1424)

* Refactor session_keys to its own package

* Adjust play_tracker

- Don't send external NowPlaying/Scrobble for tracks with unknown artist
- Continue to the next agent on error

* Implement ListenBrainz Agent and Auth Router

* Implement frontend for ListenBrainz linking

* Update listenBrainzRequest

- Don't marshal Player to json
- Rename Track to Title

* Return ErrRetryLater on ListenBrainz server errors

* Add tests for listenBrainzAgent

* Add tests for ListenBrainz Client

* Adjust ListenBrainzTokenDialog to handle errors better

* Refactor listenbrainz.formatListen and listenBrainzRequest structs

* Refactor agent auth_routers

* Refactor session_keys to agents package

* Add test for listenBrainzResponse

* Add tests for ListenBrainz auth_router

* Update ListenBrainzTokenDialog and auth_router

* Adjust player scrobble toggle

core/scrobbler/play_tracker_test.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/navidrome/navidrome/conf"
+	"github.com/navidrome/navidrome/consts"
 
 	"github.com/navidrome/navidrome/model"
 	"github.com/navidrome/navidrome/model/request"
@@ -78,6 +79,14 @@ var _ = Describe("PlayTracker", func() {
 
 			err := tracker.NowPlaying(ctx, "player-1", "player-one", "123")
 
+			Expect(err).ToNot(HaveOccurred())
+			Expect(fake.NowPlayingCalled).To(BeFalse())
+		})
+		It("does not send track to agent if artist is unknown", func() {
+			track.Artist = consts.UnknownArtist
+
+			err := tracker.NowPlaying(ctx, "player-1", "player-one", "123")
+
 			Expect(err).ToNot(HaveOccurred())
 			Expect(fake.NowPlayingCalled).To(BeFalse())
 		})
@@ -146,7 +155,7 @@ var _ = Describe("PlayTracker", func() {
 			Expect(fake.ScrobbleCalled).To(BeFalse())
 		})
 
-		It("does not send track to agent player is not enabled to send scrobbles", func() {
+		It("does not send track to agent if player is not enabled to send scrobbles", func() {
 			ctx = request.WithPlayer(ctx, model.Player{ScrobbleEnabled: false})
 
 			err := tracker.Submit(ctx, []Submission{{TrackID: "123", Timestamp: time.Now()}})
@@ -155,6 +164,15 @@ var _ = Describe("PlayTracker", func() {
 			Expect(fake.ScrobbleCalled).To(BeFalse())
 		})
 
+		It("does not send track to agent if artist is unknown", func() {
+			track.Artist = consts.UnknownArtist
+
+			err := tracker.Submit(ctx, []Submission{{TrackID: "123", Timestamp: time.Now()}})
+
+			Expect(err).ToNot(HaveOccurred())
+			Expect(fake.ScrobbleCalled).To(BeFalse())
+		})
+
 		It("increments play counts even if it cannot scrobble", func() {
 			fake.Error = errors.New("error")