feat: Generate Nginx WAF config with separate map and rule files

This commit modifies the script to output two files:
- waf_maps.conf (for http block)
- waf_rules.conf (for server block)
to avoid conflicts and provide more flexibility.

This update should fix the bugged nginx rules integration on existing setups: https://github.com/fabriziosalmi/patterns/issues/8

waf_patterns/nginx/README.md

@@ -1,22 +1,30 @@
-# Nginx WAF Rule Snippets
+# Nginx WAF Configuration
 
-This directory contains Nginx WAF rule snippets generated from OWASP rules.
-You can include these snippets in your existing Nginx configuration to enhance security.
+This directory contains Nginx WAF configuration files generated from OWASP rules.
+You can include these files in your existing Nginx configuration to enhance security.
 
 ## Usage
-1. Include the rule snippets in your `server` or `location` block:
+1. Include the `waf_maps.conf` file in your `nginx.conf` *inside the `http` block*:
    ```nginx
-   server {
-       # Your existing configuration
-       include /path/to/waf_patterns/nginx/*.conf;
+   http {
+       include /path/to/waf_patterns/nginx/waf_maps.conf;
+       # ... other http configurations ...
    }
    ```
-2. Reload Nginx to apply the changes:
+2. Include the `waf_rules.conf` file in your `server` block:
+   ```nginx
+   server {
+       # ... other server configurations ...
+       include /path/to/waf_patterns/nginx/waf_rules.conf;
+   }
+   ```
+3. Reload Nginx to apply the changes:
    ```bash
    sudo nginx -t && sudo systemctl reload nginx
    ```
 
 ## Notes
-- The rules use `map` directives for efficient pattern matching.
+- The rules use `map` directives for efficient pattern matching. The maps are defined in the `waf_maps.conf` file.
+- The rules (if statements) are defined in the `waf_rules.conf` file.
 - Blocked requests return a `403 Forbidden` response by default.
 - You can enable logging for blocked requests by uncommenting the `access_log` line.