refactor: Remove RedHat/CentOS support, focus on Ubuntu/Debian

BREAKING CHANGE: Removed RedHat/CentOS/Rocky Linux support to improve stability

- Remove all RedHat/CentOS-specific code and variables
- Consolidate Ubuntu/Debian variables into single debian-family.yml
- Simplify CI/CD pipeline (remove CentOS tests)
- Remove unstable multi-OS complexity
- Update documentation to reflect Ubuntu/Debian focus
- Streamline playbooks for better maintainability

This change makes the project more stable and maintainable by focusing
on the most common server distributions (Ubuntu/Debian) instead of
trying to support multiple OS families with different package managers
and configurations.

templates/wordpress-redhat.nginx.j2

@@ -1,75 +0,0 @@
-server {
-    listen 80;
-    server_name {{ domain_name | default('_') }};
-    
-    root {{ wordpress_path }};
-    index index.php index.html index.htm;
-    
-    # Logging
-    access_log {{ log_dir }}/nginx/wordpress_access.log;
-    error_log {{ log_dir }}/nginx/wordpress_error.log;
-    
-    # WordPress specific rules
-    location / {
-        try_files $uri $uri/ /index.php?$args;
-    }
-    
-    location ~ \.php$ {
-        fastcgi_pass unix:{{ php_fpm_socket }};
-        fastcgi_index index.php;
-        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
-        include fastcgi_params;
-        
-        # Security
-        fastcgi_hide_header X-Powered-By;
-    }
-    
-    # Deny access to hidden files
-    location ~ /\. {
-        deny all;
-        access_log off;
-        log_not_found off;
-    }
-    
-    # WordPress uploads
-    location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg)$ {
-        expires 1y;
-        add_header Cache-Control "public, immutable";
-        access_log off;
-    }
-    
-    # WordPress security
-    location ~* ^/(wp-config\.php|wp-config-sample\.php|readme\.html|license\.txt)$ {
-        deny all;
-        access_log off;
-        log_not_found off;
-    }
-    
-    # Deny access to any files with a .php extension in the uploads directory
-    location ~* /(?:uploads|files)/.*\.php$ {
-        deny all;
-        access_log off;
-        log_not_found off;
-    }
-    
-    # WordPress REST API and XMLRPC protection
-    location = /xmlrpc.php {
-        deny all;
-        access_log off;
-        log_not_found off;
-    }
-    
-    # Block access to wp-includes folders and files
-    location ~* ^/wp-includes/.*.php$ {
-        deny all;
-        access_log off;
-        log_not_found off;
-    }
-    
-    # Block wp-content/uploads php files
-    location ~* ^/wp-content/uploads/.*.php$ {
-        deny all;
-        access_log off;
-        log_not_found off;
-    }
-}