feat: Remove deprecated test files and enhance documentation for version 3.3.0 "Nexus Infinitum"

- Deleted obsolete test files: test_mime.go, test_mime_integration.go, and xmpp_client_upload_diagnosis.ipynb.
- Updated README.md to reflect the new version 3.3.0 "Nexus Infinitum" and its features.
- Added comprehensive release notes for version 3.3.0 detailing major enhancements and installation instructions.
- Introduced cleanup script to remove development artifacts while preserving production files.

installer.sh

@@ -1027,7 +1027,7 @@ create_systemd_service() {
     cat > /etc/systemd/system/hmac-file-server.service << EOF
 [Unit]
 Description=HMAC File Server 3.2
-Documentation=https://github.com/PlusOne/hmac-file-server
+Documentation=https://git.uuxo.net/uuxo/hmac-file-server/
 After=network.target
 Wants=network-online.target
 EOF
@@ -1329,9 +1329,9 @@ print_completion_info() {
     echo -e "5. Test file uploads with your XMPP client"
     echo ""
     echo -e "${BLUE}Documentation & Support:${NC}"
-    echo -e "  README: https://github.com/PlusOne/hmac-file-server/blob/main/README.MD"
-    echo -e "  Wiki:   https://github.com/PlusOne/hmac-file-server/blob/main/WIKI.MD"
-    echo -e "  Issues: https://github.com/PlusOne/hmac-file-server/issues"
+    echo -e "  README: https://git.uuxo.net/uuxo/hmac-file-server/blob/main/README.MD"
+    echo -e "  Wiki:   https://git.uuxo.net/uuxo/hmac-file-server/blob/main/WIKI.MD"
+    echo -e "  Issues: https://git.uuxo.net/uuxo/hmac-file-server/issues"
     echo ""
     echo -e "${GREEN}----------------------------------------------------------------${NC}"
     echo -e "${GREEN}    Thank you for choosing HMAC File Server for your XMPP setup! ${NC}"