added Screenshot, desktop file and metainfo directives for install

com.angoosh.doublecmd/com.angoosh.doublecmd.desktop

@@ -0,0 +1,6 @@
+[Desktop Entry]
+Name=Double Commander
+Exec=doublecmd
+Type=Application
+Icon=com.angoosh.doublecmd
+Categories=Office;GTK

com.angoosh.doublecmd/com.angoosh.doublecmd.yml

@@ -20,14 +20,16 @@ modules:
       - mv doublecmd/* /app/bin
       - mkdir -p /app/share/icons/hicolor/48x48/apps/
       - mkdir -p /app/share/applications/
+      - mkdir -p /app/share/metainfo/
       - cp /app/bin/doublecmd.png /app/share/icons/hicolor/48x48/apps/com.angoosh.doublecmd.png
-      - echo "[Desktop Entry]" >> /app/share/applications/com.angoosh.doublecmd.desktop
-      - echo "Name=Double Commander" >> /app/share/applications/com.angoosh.doublecmd.desktop
-      - echo "Exec=doublecmd" >> /app/share/applications/com.angoosh.doublecmd.desktop
-      - echo "Type=Application" >> /app/share/applications/com.angoosh.doublecmd.desktop
-      - echo "Icon=com.angoosh.doublecmd" >> /app/share/applications/com.angoosh.doublecmd.desktop
-      - echo "Categories=Office;X-Tool" >> /app/share/applications/com.angoosh.doublecmd.desktop
+      - install -Dm644 com.angoosh.doublecmd.desktop /app/share/applications
+      - install -Dm644 com.angoosh.doublecmd.metainfo.xml /app/share/metainfo
+      
     sources:
       - type: file
         path: ./doublecmd.zip
         dest-filename: doublecmd.zip
+      - type: file
+        path: com.angoosh.doublecmd.desktop
+      - type: file
+        path: com.angoosh.doublecmd.metainfo.xml