Implement v4 endpoints for OAuth (#6040)

* Implement POST /oauth/apps endpoint for APIv4

* Implement GET /oauth/apps endpoint for APIv4

* Implement GET /oauth/apps/{app_id} and /oauth/apps/{app_id}/info endpoints for APIv4

* Refactor API version independent oauth endpoints

* Implement DELETE /oauth/apps/{app_id} endpoint for APIv4

* Implement /oauth/apps/{app_id}/regen_secret endpoint for APIv4

* Implement GET /user/{user_id}/oauth/apps/authorized endpoint for APIv4

* Implement POST /oauth/deauthorize endpoint

model/authorize_test.go

@@ -20,6 +20,17 @@ func TestAuthJson(t *testing.T) {
 	if a1.Code != ra1.Code {
 		t.Fatal("codes didn't match")
 	}
+
+	a2 := AuthorizeRequest{}
+	a2.ClientId = NewId()
+	a2.Scope = NewId()
+
+	json = a2.ToJson()
+	ra2 := AuthorizeRequestFromJson(strings.NewReader(json))
+
+	if a2.ClientId != ra2.ClientId {
+		t.Fatal("client ids didn't match")
+	}
 }
 
 func TestAuthPreSave(t *testing.T) {