[vulkan, android] Add feature of post-processing shaders on Android (#4348)

Very self-explanatory; implementation of the feature for post-processing shaders for Android (at least for now); will allow users to enhance the graphic quality of video games based on the use of multiple shaders adjustable, presets and more, inspired on the PPSSPP implementation, this feature adds 22 customizable shaders (1 pass) that lives on the overlay of the screen, which means that aside of the capability to chain multiple shaders on the screen, this doesn't have depths (pixel/ depth z-buffer) so it ensures the performance with it's use. Few shaders were a faithful port from PPSSPP with their respective attribution on the shader headers for their respective owners; and there are adaptations from public references/ cinematographic (Anime4K) and the rest are my own addition.

_Special Credits:_

1.- PPSSPP Team for their contribution on the public references for shaders: Henrik Rydgard, ShadX, SimoneT, KillaMaaki and guest(r).
2.- Niklas Haas.
3.- bloc97.

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4348
Reviewed-by: lizzie <lizzie@eden-emu.dev>
Reviewed-by: Maufeat <sahyno1996@gmail.com>

src/video_core/post_processing/GenerateBundledPresets.cmake

@@ -0,0 +1,50 @@
+# SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+set(PRESET_DIR ${CMAKE_ARGV3})
+set(HEADER_FILE ${CMAKE_ARGV4})
+
+file(GLOB PRESET_FILES ${PRESET_DIR}/*.fxp)
+list(SORT PRESET_FILES)
+
+set(ENTRIES "")
+foreach(PRESET_FILE IN LISTS PRESET_FILES)
+    get_filename_component(PRESET_NAME ${PRESET_FILE} NAME)
+    file(READ ${PRESET_FILE} PRESET_BODY)
+
+    string(REGEX REPLACE ";" "{{SEMICOLON}}" PRESET_BODY "${PRESET_BODY}")
+    string(REGEX REPLACE "\n" ";" PRESET_BODY "${PRESET_BODY}")
+
+    set(PRESET_TEXT "")
+    foreach(LINE IN LISTS PRESET_BODY)
+        string(CONCAT PRESET_TEXT "${PRESET_TEXT}" "        R\"(${LINE}\n)\"\n")
+    endforeach()
+    string(REGEX REPLACE "{{SEMICOLON}}" ";" PRESET_TEXT "${PRESET_TEXT}")
+
+    string(CONCAT ENTRIES "${ENTRIES}"
+        "    {\n        \"${PRESET_NAME}\",\n${PRESET_TEXT}    },\n")
+endforeach()
+
+get_filename_component(OUTPUT_DIR ${HEADER_FILE} DIRECTORY)
+make_directory(${OUTPUT_DIR})
+
+file(WRITE ${HEADER_FILE}
+"// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#pragma once
+
+#include <string_view>
+
+namespace VideoCore {
+
+struct BundledFxPreset {
+    std::string_view name;
+    std::string_view source;
+};
+
+constexpr BundledFxPreset BUNDLED_FX_PRESETS[]{
+${ENTRIES}};
+
+} // namespace VideoCore
+")