Remove glium recipe

Glium is no longer actively maintained.

recipes/demos/glium/recipe.sh

-GIT=https://gitlab.redox-os.org/redox-os/glium.git
-GIT_UPSTREAM=https://github.com/glium/glium.git
-BUILD_DEPENDS=(llvm18 mesa zlib)
-BRANCH=redox
-CARGOFLAGS="--example teapot"
-
-function recipe_build {
-    sysroot="$(realpath ../sysroot)"
-    set -x
-    cargo rustc --target "$TARGET" --release ${CARGOFLAGS} \
-        -- \
-        -L "${sysroot}/lib" \
-        -C link-args="-Wl,-Bstatic $("${PKG_CONFIG}" --libs osmesa) -lz -lstdc++ -lc -lgcc"
-    set +x
-    skip=1
-}
-
-function recipe_stage {
-    dest="$(realpath $1)"
-    mkdir -pv "$dest/bin"
-    cp -v "target/${TARGET}/release/examples/teapot" "$dest/bin/glium"
-    skip=1
-}