N°3526 - Clean up pass on UIBlocks

- Move UIBlock::ENUM_BLOCK_FILES_TYPE_XXX to iUIBlock
- Add PHPDoc
- Remove Object return type hint on overloadable methods
- Add scalar return type hint
- Add type hint on parameters

sources/application/UI/Base/Component/PopoverMenu/NewsroomMenu/NewsroomMenu.php

@@ -61,7 +61,7 @@ class NewsroomMenu extends PopoverMenu
 	 *
 	 * @return false|string
 	 */
-	public function GetParamsAsJson()
+	public function GetParamsAsJson(): string
 	{
 		return json_encode($this->aParams);
 	}