feat: Integrate Docusaurus for documentation and enhance project structure

- Added Docusaurus configuration and initial setup for documentation.
- Created multiple documentation pages covering installation, configuration, and core concepts.
- Implemented a GitHub Actions workflow for automatic deployment of documentation to GitHub Pages.
- Updated .gitignore to exclude Docusaurus build artifacts and dependencies.
- Enhanced README with a link to the online documentation.

docs/sidebars.ts

@@ -0,0 +1,58 @@
+import type {SidebarsConfig} from '@docusaurus/plugin-content-docs';
+
+// This runs in Node.js - Don't use client-side code here (browser APIs, JSX...)
+
+/**
+ * Creating a sidebar enables you to:
+ - create an ordered group of docs
+ - render a sidebar for each doc of that group
+ - provide next/previous navigation
+
+ The sidebars can be generated from the filesystem, or explicitly defined here.
+
+ Create as many sidebars as you want.
+ */
+const sidebars: SidebarsConfig = {
+  docsSidebar: [
+    {
+      type: 'category',
+      label: 'Introduction',
+      items: ['introduction/overview', 'introduction/features'],
+    },
+    {
+      type: 'category',
+      label: 'Getting Started',
+      items: ['getting-started/installation', 'getting-started/configuration', 'getting-started/quick-start', 'getting-started/docker', 'getting-started/traditional'],
+    },
+    {
+      type: 'category',
+      label: 'Core Concepts',
+      items: ['core-concepts/transfers', 'core-concepts/connections', 'core-concepts/schedules', 'core-concepts/monitoring'],
+    },
+    {
+      type: 'category',
+      label: 'Advanced Features',
+      items: [
+        'advanced/notifications-overview',
+        'advanced/gotify-notifications',
+        'advanced/ntfy-notifications',
+        'advanced/pushbullet-notifications',
+        'advanced/pushover-notifications',
+        'advanced/webhook-notifications',
+        'advanced/admin-tools'
+      ],
+    },
+    {
+      type: 'category',
+      label: 'Security',
+      items: ['security/best-practices', 'security/authentication', 'security/non-root'],
+    },
+    {
+      type: 'category',
+      label: 'Development',
+      items: ['development/project-structure', 'development/contributing'],
+    },
+  ],
+};
+
+export default sidebars;