Remove SDL3_main from build systems, remove most of src/main/*

XCode is still missing, and src/main/winrt/SDL3-WinRTResource*
still need to find a new home

build-scripts/android-prefab.sh

@@ -61,7 +61,6 @@ build_cmake_projects() {
             -DSDL_STATIC=ON \
             -DSDL_STATIC_PIC=ON \
             -DSDL_TEST=ON \
-            -DSDL3_DISABLE_SDL3MAIN=OFF \
             -DSDL3_DISABLE_INSTALL=OFF \
             -DCMAKE_INSTALL_PREFIX="${build_root}/build_${android_abi}/prefix" \
             -DCMAKE_INSTALL_INCLUDEDIR=include \
@@ -252,35 +251,6 @@ EOF
     done
 }
 
-create_sdlmain_module() {
-    echo "Creating SDL${sdl_major}main prefab module"
-    for android_abi in $android_abis; do
-        sdl_moduleworkdir="${modulesworkdir}/SDL${sdl_major}main"
-        mkdir -p "${sdl_moduleworkdir}"
-
-        abi_build_prefix="${build_root}/build_${android_abi}/prefix"
-
-        cat >"${sdl_moduleworkdir}/module.json" <<EOF
-{
-  "export_libraries": [],
-  "library_name": "libSDL${sdl_major}main"
-}
-EOF
-        abi_sdllibdir="${sdl_moduleworkdir}/libs/android.${android_abi}"
-        mkdir -p "${abi_sdllibdir}"
-        cat >"${abi_sdllibdir}/abi.json" <<EOF
-{
-  "abi": "${android_abi}",
-  "api": ${android_api},
-  "ndk": ${android_ndk},
-  "stl": "${android_stl}",
-  "static": true
-}
-EOF
-        cp "${abi_build_prefix}/lib/libSDL${sdl_major}main.a" "${abi_sdllibdir}"
-    done
-}
-
 create_sdltest_module() {
     echo "Creating SDL${sdl_major}test prefab module"
     for android_abi in $android_abis; do
@@ -322,8 +292,6 @@ create_shared_sdl_module
 
 create_static_sdl_module
 
-create_sdlmain_module
-
 create_sdltest_module
 
 pushd "${aar_root}"