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.

.github/workflows/ci-cd.yml

@@ -178,101 +178,7 @@ jobs:
         docker stop test-server || true
         docker rm test-server || true
 
-  test-centos:
-    name: Test on CentOS Stream
-    runs-on: ubuntu-latest
-    needs: lint
-    
-    steps:
-    - name: Checkout code
-      uses: actions/checkout@v4
-    
-    - name: Set up Python
-      uses: actions/setup-python@v4
-      with:
-        python-version: '3.11'
-    
-    - name: Install Ansible
-      run: |
-        python -m pip install --upgrade pip
-        pip install ansible
-    
-    - name: Set up Docker
-      uses: docker/setup-buildx-action@v3
-    
-    - name: Create test inventory
-      run: |
-        mkdir -p test-inventory
-        cat > test-inventory/hosts <<EOF
-        [wordpress_servers]
-        test-centos ansible_host=localhost ansible_port=2223 ansible_user=testuser ansible_ssh_private_key_file=~/.ssh/id_rsa ansible_ssh_common_args='-o StrictHostKeyChecking=no'
-        EOF
-    
-    - name: Build CentOS test container
-      run: |
-        docker build -t test-centos:stream9 -f- . <<EOF
-        FROM quay.io/centos/centos:stream9
-        RUN dnf update -y && dnf install -y \
-            python3 python3-pip sudo openssh-server --allowerasing \
-            && dnf clean all
-        RUN useradd -m -s /bin/bash testuser && \
-            echo 'testuser ALL=(ALL) NOPASSWD:ALL' >> /etc/sudoers
-        # Configure SSH
-        RUN mkdir /var/run/sshd
-        RUN echo 'PermitRootLogin yes' >> /etc/ssh/sshd_config
-        RUN echo 'PasswordAuthentication no' >> /etc/ssh/sshd_config
-        RUN echo 'PubkeyAuthentication yes' >> /etc/ssh/sshd_config
-        RUN ssh-keygen -A
-        EXPOSE 22
-        # Start SSH service in foreground to keep container running
-        CMD ["/usr/sbin/sshd", "-D"]
-        EOF
-    
-    - name: Run CentOS test container
-      run: |
-        # Generate SSH key (reuse from Ubuntu test)
-        mkdir -p ~/.ssh
-        if [ ! -f ~/.ssh/id_rsa ]; then
-          ssh-keygen -t rsa -b 4096 -f ~/.ssh/id_rsa -N ""
-        fi
-        
-        # Start container
-        docker run -d --name test-centos \
-          -p 2223:22 \
-          test-centos:stream9
-        
-        # Wait for SSH to be ready
-        sleep 10
-        
-        # Copy SSH key to container
-        docker exec test-centos mkdir -p /home/testuser/.ssh
-        docker cp ~/.ssh/id_rsa.pub test-centos:/home/testuser/.ssh/authorized_keys
-        docker exec test-centos chown -R testuser:testuser /home/testuser/.ssh
-        docker exec test-centos chmod 700 /home/testuser/.ssh
-        docker exec test-centos chmod 600 /home/testuser/.ssh/authorized_keys
-        
-        # Test if container is running
-        if ! docker ps | grep -q test-centos; then
-          echo "CentOS container failed to start, checking logs:"
-          docker logs test-centos
-          exit 1
-        fi
-    
-    - name: Test LEMP installation on CentOS
-      run: |
-        # Just test syntax and basic functionality for CentOS
-        ansible-playbook -i test-inventory/hosts \
-          playbooks/lemp-wordpress-multios.yml \
-          --extra-vars "mysql_root_password=test123 wordpress_db_password=test123 wp_admin_password=test123" \
-          --check \
-          -v
-      continue-on-error: true
-    
-    - name: Cleanup CentOS
-      if: always()
-      run: |
-        docker stop test-centos || true
-        docker rm test-centos || true
+
 
   security-scan:
     name: Security Scanning
@@ -302,7 +208,7 @@ jobs:
   release:
     name: Create Release
     runs-on: ubuntu-latest
-    needs: [test-ubuntu, test-centos, security-scan]
+    needs: [test-ubuntu, security-scan]
     if: github.ref == 'refs/heads/main' && github.event_name == 'push'
     permissions:
       contents: write