feat: Implement initial application structure with network view and SVG editor

- Added network-view.js for visualizing network topology with devices and connections.
- Introduced svg-editor.js for managing ports on device types with drag-and-drop functionality.
- Created bootstrap.php for application initialization, including configuration and database connection.
- Established config.php for centralized configuration settings.
- Developed index.php as the main entry point with module-based routing.
- Integrated _sql.php for database abstraction.
- Added auth.php for single-user authentication handling.
- Included helpers.php for utility functions.
- Created modules for managing connections, device types, devices, and floors.
- Implemented database schema in init.sql for locations, buildings, floors, rooms, network outlets, devices, and connections.
- Added Docker support with docker-compose.yml for web and database services.
- Documented database structure and UI/UX concepts in respective markdown files.

doc/DATEISTRUKTUR.md

@@ -0,0 +1,11 @@
+# Dateistruktur
+
+```php
+<?php
+ob_start();
+// HTML / Modul-Logik
+echo "<h2>Gerätetypen</h2>";
+$content = ob_get_clean();
+
+include __DIR__ . '/../templates/layout.php';
+```