refactor: consolidate all roles into ansible/roles/ and update ansible.cfg

- Move all roles from playbooks/roles/ to roles/
- Update roles_path in ansible.cfg
- Add cast user to common role
- Create standalone podman role
- Add semaphore role with Podman + Quadlet support

ansible/roles/common/tasks/main.yml

@@ -0,0 +1,21 @@
+- name: Create cast group
+  ansible.builtin.group:
+    name: cast
+    state: present
+    system: true
+
+- name: Create cast user
+  ansible.builtin.user:
+    name: cast
+    group: cast
+    shell: /bin/bash
+    create_home: true
+    state: present
+
+- name: Ensure cast user has passwordless sudo
+  ansible.builtin.lineinfile:
+    path: /etc/sudoers.d/cast
+    line: "cast ALL=(ALL) NOPASSWD:ALL"
+    create: yes
+    mode: '0440'
+    validate: 'visudo -cf %s'