Add environment variable documentation for all plugins, reorganize plugin files for consistency

- Introduced environment variable support in documentation for Cloudflare, Cleanup, Deny Pages, IP Whitelist, JWT Validator, and FastCGI plugins.
- Updated plugin files with consistent headings, examples, and tables for easier configuration reference.
- Adjusted `README.md` and `plugins.md` to reflect updated plugin paths and environment variable usage.

docs/Plugins/cleanup.md

@@ -0,0 +1,84 @@
+---
+sidebar_position: 6
+---
+
+# Cleanup Plugin
+
+**Type:** Global Plugin
+**Runs:** Once per discovery cycle
+
+## Overview
+
+The Cleanup plugin performs cleanup tasks during each discovery cycle, such as removing old temporary files.
+
+## Why Use It
+
+Prevents disk space issues by automatically cleaning up temporary files created by EasyHAProxy.
+
+## Configuration Options
+
+| Option               | Description                                  | Default |
+|----------------------|----------------------------------------------|---------|
+| `enabled`            | Enable/disable plugin                        | `true`  |
+| `max_idle_time`      | Maximum age in seconds before deleting files | `300`   |
+| `cleanup_temp_files` | Enable temp file cleanup                     | `true`  |
+
+## Configuration Examples
+
+### Static YAML Configuration
+
+```yaml
+# /etc/haproxy/static/config.yaml
+plugins:
+  enabled: [cleanup]
+  config:
+    cleanup:
+      max_idle_time: 600
+      cleanup_temp_files: true
+```
+
+### Environment Variables
+
+Configure the Cleanup plugin globally:
+
+| Environment Variable                            | Config Key           | Type     | Default | Description                                  |
+|-------------------------------------------------|----------------------|----------|---------|----------------------------------------------|
+| `EASYHAPROXY_PLUGINS_ENABLED`                   | -                    | string   | -       | Enable cleanup plugin (value: `cleanup`)     |
+| `EASYHAPROXY_PLUGIN_CLEANUP_ENABLED`            | `enabled`            | boolean  | `true`  | Enable/disable plugin                        |
+| `EASYHAPROXY_PLUGIN_CLEANUP_MAX_IDLE_TIME`      | `max_idle_time`      | integer  | `300`   | Maximum age in seconds before deleting files |
+| `EASYHAPROXY_PLUGIN_CLEANUP_CLEANUP_TEMP_FILES` | `cleanup_temp_files` | boolean  | `true`  | Enable temp file cleanup                     |
+
+**Note:** This is a global plugin - configuration applies to the entire system.
+
+### Custom Idle Time (1 hour)
+
+```yaml
+# /etc/haproxy/static/config.yaml
+plugins:
+  enabled: [cleanup]
+  config:
+    cleanup:
+      enabled: true
+      max_idle_time: 3600  # 1 hour
+```
+
+## How It Works
+
+The cleanup plugin:
+- Runs once during each discovery cycle
+- Scans temporary directories for old files
+- Removes files older than `max_idle_time` seconds
+- Helps maintain disk space efficiency
+
+## Important Notes
+
+- This is a **global plugin** - it runs once per discovery cycle, not per domain
+- Does not generate HAProxy configuration
+- Performs maintenance operations in the background
+- Safe to enable in production environments
+
+## Related Documentation
+
+- [Plugin System Overview](../plugins.md)
+- [Environment Variables Reference](../environment-variable.md)
+- [Static Configuration Reference](../static.md)