Move user properties (like session keys) to their own table

core/agents/lastfm/agent_test.go

@@ -233,7 +233,7 @@ var _ = Describe("lastfmAgent", func() {
 		var track *model.MediaFile
 		BeforeEach(func() {
 			ctx = request.WithUser(ctx, model.User{ID: "user-1"})
-			_ = ds.Property(ctx).Put(sessionKeyPropertyPrefix+"user-1", "SK-1")
+			_ = ds.UserProps(ctx).Put(sessionKeyProperty, "SK-1")
 			httpClient = &tests.FakeHttpClient{}
 			client := NewClient("API_KEY", "SECRET", "en", httpClient)
 			agent = lastFMConstructor(ds)