Rebrand the launcher to make it more distinctly GZDoom

- Use a Light theme to clearly differentiate GZDoom from VKDoom
- Moved the version label to not visually clash with the banner graphics
- Added unique graphics for the banner and the BOOTLOGO
- Changed the loading bar color to match GZDoom's logo

src/common/startscreen/startscreen_generic.cpp

@@ -106,7 +106,7 @@ bool FGenericStartScreen::DoProgress(int advance)
 
 	if (CurPos < MaxPos)
 	{
-		RgbQuad bcolor = { 2, 25, 87, 255 }; // todo: make configurable
+		RgbQuad bcolor = { 177, 77, 16, 255 }; // [Nash June 2025] don't merge this color into VKDoom! // todo: make configurable 
 		int numnotches = 200 * 2;
 		notch_pos = ((CurPos + 1) * numnotches) / MaxPos;
 		if (notch_pos != NotchPos)

src/common/widgets/widgetresourcedata.cpp

@@ -23,7 +23,7 @@ void InitWidgetResources(const char* filename)
 	if (!WidgetResources)
 		I_FatalError("Unable to open %s", filename);
 
-	WidgetTheme::SetTheme(std::make_unique<DarkWidgetTheme>());
+	WidgetTheme::SetTheme(std::make_unique<LightWidgetTheme>()); // GZDoom uses a different theme than VKDoom
 }
 
 void CloseWidgetResources()