Get album info (when available) from Last.fm, add getAlbumInfo endpoint (#2061)

* lastfm album.getInfo, getAlbuminfo(2) endpoints

* ... for description and reduce not found log level

* address first comments

* return all images

* Update migration timestamp

* Handle a few edge cases

* Add CoverArtPriority option to retrieve albumart from external sources

* Make agents methods more descriptive

* Use Last.fm name consistently

Co-authored-by: Deluan <deluan@navidrome.org>

server/subsonic/responses/responses_test.go

@@ -335,6 +335,39 @@ var _ = Describe("Responses", func() {
 		})
 	})
 
+	Describe("AlbumInfo", func() {
+		BeforeEach(func() {
+			response.AlbumInfo = &AlbumInfo{}
+		})
+
+		Context("without data", func() {
+			It("should match .XML", func() {
+				Expect(xml.Marshal(response)).To(MatchSnapshot())
+			})
+			It("should match .JSON", func() {
+				Expect(json.Marshal(response)).To(MatchSnapshot())
+			})
+		})
+
+		Context("with data", func() {
+			BeforeEach(func() {
+				response.AlbumInfo.SmallImageUrl = "https://lastfm.freetls.fastly.net/i/u/34s/3b54885952161aaea4ce2965b2db1638.png"
+				response.AlbumInfo.MediumImageUrl = "https://lastfm.freetls.fastly.net/i/u/64s/3b54885952161aaea4ce2965b2db1638.png"
+				response.AlbumInfo.LargeImageUrl = "https://lastfm.freetls.fastly.net/i/u/174s/3b54885952161aaea4ce2965b2db1638.png"
+				response.AlbumInfo.LastFmUrl = "https://www.last.fm/music/Cher/Believe"
+				response.AlbumInfo.MusicBrainzID = "03c91c40-49a6-44a7-90e7-a700edf97a62"
+				response.AlbumInfo.Notes = "Believe is the twenty-third studio album by American singer-actress Cher..."
+			})
+
+			It("should match .XML", func() {
+				Expect(xml.Marshal(response)).To(MatchSnapshot())
+			})
+			It("should match .JSON", func() {
+				Expect(json.Marshal(response)).To(MatchSnapshot())
+			})
+		})
+	})
+
 	Describe("ArtistInfo", func() {
 		BeforeEach(func() {
 			response.ArtistInfo = &ArtistInfo{}