chore: align repository and Ansible configuration

Relocate group variable examples beside the inventory for automatic discovery.

Refresh repository guidance, ignore local tooling artifacts, and disable Ansible cows.

ansible/inventory/group_vars/all/main.yml.example

@@ -0,0 +1,22 @@
+app_user: todo
+app_image: registry.example.com/todo:latest
+app_port: 8080
+app_db_name: todo
+app_db_user: todo_app
+
+postgres_data_dir: /var/lib/pgsql/data
+postgres_service: postgresql
+
+wal_g_version: v3.0.7
+wal_g_download_url: "https://github.com/wal-g/wal-g/releases/download/{{ wal_g_version }}/wal-g-pg-ubuntu-20.04-amd64.tar.gz"
+wal_g_s3_prefix: s3://replace-with-backup-bucket/prod
+wal_g_s3_endpoint: https://nbg1.your-objectstorage.com
+wal_g_s3_region: nbg1
+wal_g_access_key: "replace-with-object-storage-access-key"
+wal_g_secret_key: "replace-with-object-storage-secret-key"
+wal_g_retention_count: 7
+
+# Optional private registry credentials. Omit both for public images.
+# registry_username: registry-user
+# registry_password: registry-password
+# registry_server: registry.example.com

ansible/inventory/group_vars/prod/vault.yml.example

@@ -0,0 +1 @@
+app_db_password: "replace-with-production-database-password"

ansible/inventory/group_vars/staging/vault.yml.example

@@ -0,0 +1 @@
+app_db_password: "replace-with-distinct-staging-database-password"