Add LocalSend send action in Nautilus (#4946)

* Add LocalSend send action in Nautilus

* Reuse Nautilus install script in migration

* Detect LocalSend via PATH

* Verify Flatpak LocalSend is installed

* Check Flatpak LocalSend with flatpak info

install/config/nautilus-python.sh

@@ -0,0 +1,4 @@
+EXTENSIONS_DIR="$HOME/.local/share/nautilus-python/extensions"
+
+mkdir -p "$EXTENSIONS_DIR"
+cp "$OMARCHY_PATH/default/nautilus-python/extensions/localsend.py" "$EXTENSIONS_DIR/"