common: Move image decoders to common

* Replace the various image interfaces with spng which is very lightweight and fast. Also add a dds header which will be useful when support for that format is implemented

externals/CMakeLists.txt

@@ -178,8 +178,8 @@ if (ENABLE_WEB_SERVICE)
     target_compile_definitions(cpp-jwt INTERFACE CPP_JWT_USE_VENDORED_NLOHMANN_JSON)
 endif()
 
-# lodepng
-add_subdirectory(lodepng)
+# libspng
+add_subdirectory(libspng)
 
 # (xperia64): Only use libyuv on Android b/c of build issues on Windows and mandatory JPEG
 if(ANDROID)

externals/lodepng/CMakeLists.txt

@@ -1,7 +0,0 @@
-add_library(lodepng
-    lodepng/lodepng.cpp
-    lodepng/lodepng.h
-)
-
-create_target_directory_groups(lodepng)
-target_include_directories(lodepng INTERFACE lodepng)