Miscallenious fixes to gl backend and qt frontend (#6834)

* renderer_gl: Make rasterizer normal class member

* It doesn't need to be heap allocated anymore

* gl_rasterizer: Remove default_texture

* It's unused

* gl_rasterizer: General cleanup

* gl_rasterizer: Lower case lambdas

* Match style with review comments from vulkan backend

* rasterizer_cache: Prevent memory leak

* Since the switch from shared_ptr these surfaces were no longer being destroyed properly. Use our garbage collector for that purpose to destroy it safely for both backends

* rasterizer_cache: Make temp copy of old surface

* The custom surface would override the memory region of the old region resulting in garbage data, this ensures the custom surface is constructed correctly

* citra_qt: Manually create dialog tabs

* Allows for custom constructors which is very useful. While at it, global state is now eliminated from configuration

* citra_qt: Eliminate global system usage

* core: Remove global system usage in memory and HIO

* citra_qt: Use qOverload

* tests: Run clang format

* gl_texture_runtime: Fix surface scaling

src/citra_qt/configuration/configure_enhancements.cpp

@@ -22,8 +22,7 @@ ConfigureEnhancements::ConfigureEnhancements(QWidget* parent)
     const bool res_scale_enabled = graphics_api != Settings::GraphicsAPI::Software;
     ui->resolution_factor_combobox->setEnabled(res_scale_enabled);
 
-    connect(ui->render_3d_combobox,
-            static_cast<void (QComboBox::*)(int)>(&QComboBox::currentIndexChanged), this,
+    connect(ui->render_3d_combobox, qOverload<int>(&QComboBox::currentIndexChanged), this,
             [this](int currentIndex) {
                 updateShaders(static_cast<Settings::StereoRenderOption>(currentIndex));
             });