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.

test/integration/editor/editor_integration_test.cc

@@ -38,7 +38,9 @@ EditorIntegrationTest::~EditorIntegrationTest() {
 }
 
 absl::Status EditorIntegrationTest::Initialize() {
-  RETURN_IF_ERROR(core::CreateWindow(window_, SDL_WINDOW_RESIZABLE));
+  // Create renderer for test
+  test_renderer_ = std::make_unique<gfx::SDL2Renderer>();
+  RETURN_IF_ERROR(core::CreateWindow(window_, test_renderer_.get(), SDL_WINDOW_RESIZABLE));
 
   IMGUI_CHECKVERSION();
   ImGui::CreateContext();
@@ -55,9 +57,9 @@ absl::Status EditorIntegrationTest::Initialize() {
   io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
 
   // Initialize ImGui for SDL
-  ImGui_ImplSDL2_InitForSDLRenderer(
-      controller_.window(), yaze::core::Renderer::Get().renderer());
-  ImGui_ImplSDLRenderer2_Init(yaze::core::Renderer::Get().renderer());
+  SDL_Renderer* sdl_renderer = static_cast<SDL_Renderer*>(test_renderer_->GetBackendRenderer());
+  ImGui_ImplSDL2_InitForSDLRenderer(controller_.window(), sdl_renderer);
+  ImGui_ImplSDLRenderer2_Init(sdl_renderer);
 
 #ifdef YAZE_ENABLE_IMGUI_TEST_ENGINE
   // Register tests