chore(vcpkg): remove SDL2 overlay and related configurations

- Eliminated the custom vcpkg overlay for SDL2, which was previously used to address installation issues on Windows.
- Updated `vcpkg.json` to remove SDL2 dependency and related configurations from CI and release workflows.
- Deleted associated documentation and files for the SDL2 overlay to streamline the project structure.

Benefits:
- Simplifies the vcpkg configuration by removing unnecessary overlays, improving maintainability.
- Reduces complexity in the CI and release processes, enhancing overall build reliability.

vcpkg.json

@@ -5,12 +5,6 @@
   "description": "Yet Another Zelda3 Editor",
   "builtin-baseline": "7ba0ba7334c3346e7eee1e049ba85da193a8d821",
   "dependencies": [
-    {
-      "name": "sdl2",
-      "platform": "windows",
-      "default-features": false,
-      "features": []
-    },
     {
       "name": "yaml-cpp",
       "platform": "windows"
@@ -19,11 +13,5 @@
       "name": "zlib",
       "platform": "windows"
     }
-  ],
-  "overrides": [
-    {
-      "name": "sdl2",
-      "version": "2.30.9"
-    }
   ]
 }