packaging: add dms-open.desktop and danklogo.svg to all distributions

- Add dms-open.desktop to /usr/share/applications
- Add danklogo.svg to /usr/share/icons/hicolor/scalable/apps
- Updated packaging for:
  - Fedora (dms.spec)
  - OpenSUSE (dms.spec, dms-git.spec)
  - Debian (dms, dms-git)
  - Ubuntu (dms, dms-git)

Fixes #860

distro/debian/dms-git/debian/rules

@@ -60,6 +60,8 @@ override_dh_auto_install:
 	if [ -d quickshell ]; then \
 		cp -r quickshell/* debian/dms-git/usr/share/quickshell/dms/; \
 		install -Dm644 quickshell/assets/systemd/dms.service debian/dms-git/usr/lib/systemd/user/dms.service; \
+		install -Dm644 assets/dms-open.desktop debian/dms-git/usr/share/applications/dms-open.desktop; \
+		install -Dm644 core/assets/danklogo.svg debian/dms-git/usr/share/icons/hicolor/scalable/apps/danklogo.svg; \
 	else \
 		echo "ERROR: quickshell directory not found!" && \
 		echo "Contents of current directory:" && ls -la && \