restic: Add stack

Adapted from cloudserve-infrastructure, implements a backup stack using
restic. The actual backups have to be implemented by individual other
roles but this sets up initialization, pruning and checking of a repository.

roles/restic/tasks/main.yml

@@ -0,0 +1,17 @@
+---
+- name: Create local backup directory
+  ansible.builtin.file:
+    state: directory
+    path: "{{ restic_repo }}"
+    owner: root
+    group: root
+    mode: 0770
+  when: restic_repo is regex('^/.+')
+
+- name: Deploy restic to compose
+  community.docker.docker_compose_v2:
+    project_name: restic
+    definition: "{{ lookup('template', 'docker-compose.yaml.j2') | from_yaml }}"
+    remove_orphans: true
+    wait: true
+    wait_timeout: 60