app: Add flatpak desktop entry

packages/app/de.provokateurin.neon.desktop

@@ -0,0 +1,6 @@
+[Desktop Entry]
+Type=Application
+Name=Nextcloud Neon
+Icon=de.provokateurin.neon
+Exec=nextcloud-neon %U
+Keywords=Nextcloud;Neon

packages/app/de.provokateurin.neon.yaml

@@ -21,7 +21,13 @@ modules:
       - ln -s /usr/lib/x86_64-linux-gnu/libsqlite3.so.0 /app/lib/libsqlite3.so
       - if [ ! -e '/app/lib/libsqlite3.so' ]; then ln -s -f /usr/lib/aarch64-linux-gnu/libsqlite3.so.0 /app/lib/libsqlite3.so; fi
       - ln -sf /app/nextcloud-neon/nextcloud-neon /app/bin/nextcloud-neon
+      - install -Dm644 de.provokateurin.neon.desktop /app/share/applications/de.provokateurin.neon.desktop
+      - install -Dm644 logo.svg /app/share/icons/hicolor/scalable/apps/de.provokateurin.neon.svg
     sources:
+      - type: file
+        path: de.provokateurin.neon.desktop
+      - type: file
+        path: assets/logo.svg
       - type: file
         path: build/linux/x64/release/bundle/nextcloud-neon
       - type: dir