feat: add wireguard secure installer with modular architecture

This commit introduces a new WireGuard VPN installer with enterprise-grade security features. The installer includes:

- Zero-touch installation with automatic configuration
- Modular architecture for maintainability (separate lib files)
- Client management interface with bandwidth monitoring
- Support for multiple Linux distributions
- Secure defaults and hardened configurations

The implementation provides a complete solution for deploying WireGuard VPN servers with minimal user interaction while maintaining security best practices.

manage.sh

@@ -0,0 +1,54 @@
+#!/bin/bash
+# WireGuard Secure Installer
+# Copyright (c) 2025 Muhammad Fadhila Abiyyu Faris
+# GitHub: [github.com/fadhila36/wireguard-secure-installer](https://github.com/fadhila36/wireguard-secure-installer)
+
+# Load Config and Libraries
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+source "$SCRIPT_DIR/config.env"
+source "$SCRIPT_DIR/lib/utils.sh"
+source "$SCRIPT_DIR/lib/network.sh"
+source "$SCRIPT_DIR/lib/wg_core.sh" # Needed for create_client_config
+source "$SCRIPT_DIR/lib/client_mgmt.sh"
+
+check_root
+
+while true; do
+    clear
+    echo -e "${BLUE}"
+    echo "================================================="
+    echo "   WireGuard Management Menu"
+    echo "================================================="
+    echo -e "${NC}"
+    echo "1. Add New Client"
+    echo "2. Remove Client"
+    echo "3. View Bandwidth Usage"
+    echo "4. Exit"
+    echo ""
+    echo -n "Select an option [1-4]: "
+    read -r OPTION
+
+    case $OPTION in
+        1)
+            new_client
+            ;;
+        2)
+            remove_client
+            ;;
+        3)
+            view_usage_logs
+            ;;
+        4)
+            echo "Exiting..."
+            exit 0
+            ;;
+        *)
+            echo "Invalid option."
+            sleep 1
+            ;;
+    esac
+    
+    echo ""
+    echo -n "Press Enter to return to menu..."
+    read -r
+done