refactor: external_metadata -> external.Provider (#3903)

* tests for TopSongs

Signed-off-by: Deluan <deluan@navidrome.org>

* convert to Ginkgo

Signed-off-by: Deluan <deluan@navidrome.org>

* consolidate tests

Signed-off-by: Deluan <deluan@navidrome.org>

* rename external metadata -wip

Signed-off-by: Deluan <deluan@navidrome.org>

* rename external metadata to extdata.Provider

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor tests - wip

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor test helpers

Signed-off-by: Deluan <deluan@navidrome.org>

* remove reflection

Signed-off-by: Deluan <deluan@navidrome.org>

* use mock.Mock

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor

Signed-off-by: Deluan <deluan@navidrome.org>

* fix

Signed-off-by: Deluan <deluan@navidrome.org>

* receive Agents interface in Provider constructor

Signed-off-by: Deluan <deluan@navidrome.org>

* use mock for Agents

Signed-off-by: Deluan <deluan@navidrome.org>

* tests for SimilarSongs

Signed-off-by: Deluan <deluan@navidrome.org>

* remove duplication

Signed-off-by: Deluan <deluan@navidrome.org>

* ArtistImage tests

Signed-off-by: Deluan <deluan@navidrome.org>

* AlbumImage tests

Signed-off-by: Deluan <deluan@navidrome.org>

* fix provider error handling

Signed-off-by: Deluan <deluan@navidrome.org>

* UpdateAlbumInfo tests - wip

Signed-off-by: Deluan <deluan@navidrome.org>

* UpdateAlbumInfo tests - wip

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor

Signed-off-by: Deluan <deluan@navidrome.org>

* UpdateArtistInfo tests - wip

Signed-off-by: Deluan <deluan@navidrome.org>

* clean up

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor

Signed-off-by: Deluan <deluan@navidrome.org>

* fix test descriptions

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor: rename extdata package to external

Signed-off-by: Deluan <deluan@navidrome.org>

---------

Signed-off-by: Deluan <deluan@navidrome.org>

core/wire_providers.go

@@ -3,6 +3,7 @@ package core
 import (
 	"github.com/google/wire"
 	"github.com/navidrome/navidrome/core/agents"
+	"github.com/navidrome/navidrome/core/external"
 	"github.com/navidrome/navidrome/core/ffmpeg"
 	"github.com/navidrome/navidrome/core/metrics"
 	"github.com/navidrome/navidrome/core/playback"
@@ -13,11 +14,12 @@ var Set = wire.NewSet(
 	NewMediaStreamer,
 	GetTranscodingCache,
 	NewArchiver,
-	NewExternalMetadata,
 	NewPlayers,
 	NewShare,
 	NewPlaylists,
 	agents.GetAgents,
+	external.NewProvider,
+	wire.Bind(new(external.Agents), new(*agents.Agents)),
 	ffmpeg.New,
 	scrobbler.GetPlayTracker,
 	playback.GetInstance,