epic: refactor SDL2_Renderer usage to IRenderer and queued texture rendering

- Updated the testing guide to clarify the testing framework's organization and execution methods, improving user understanding.
- Refactored CMakeLists to include new platform-specific files, ensuring proper integration of the rendering backend.
- Modified main application files to utilize the new IRenderer interface, enhancing flexibility in rendering operations.
- Implemented deferred texture management in various components, allowing for more efficient graphics handling and improved performance.
- Introduced new methods for texture creation and updates, streamlining the rendering process across the application.
- Enhanced logging and error handling in the rendering pipeline to facilitate better debugging and diagnostics.

src/app/editor/editor_manager.h

@@ -105,7 +105,7 @@ class EditorManager {
     context_.popup_manager = popup_manager_.get();
   }
 
-  void Initialize(const std::string& filename = "");
+  void Initialize(gfx::IRenderer* renderer, const std::string& filename = "");
   absl::Status Update();
   void DrawMenuBar();
 
@@ -262,6 +262,8 @@ class EditorManager {
   EditorSet* current_editor_set_ = nullptr;
   Editor* current_editor_ = nullptr;
   EditorSet blank_editor_set_{};
+  
+  gfx::IRenderer* renderer_ = nullptr;
 
   core::YazeProject current_project_;
   EditorContext context_;