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.

config.env

@@ -0,0 +1,18 @@
+#!/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)
+
+# Server Configuration
+SERVER_PORT=51820
+SERVER_WG_NIC="wg0"
+SERVER_DNS="1.1.1.1, 1.0.0.1"
+ALLOWED_IPS="0.0.0.0/0, ::/0"
+
+# Initial Client Configuration
+CLIENT_NAME="client_admin"
+
+# Paths
+INSTALL_DIR="/opt/wg-installer"
+LOG_FILE="/var/log/wireguard-install.log"
+WG_CONFIG="/etc/wireguard/${SERVER_WG_NIC}.conf"