components: Update svix templates for staging deployment

Related to swh/infra/sysadm-environment#5105 (closed)

1. Update redis/postgres deployments to deploy only if wanted (enabled).
2. Update redis/postgres services to deploy only if wanted (enabled).
3. Update svix-server deployment to specify the redis/postgres DSN.
4. Update test-staging-rke2 values to enable redis/postgres (so nothing will be change).
5. Add archive-staging-rke2 values to only deploy svix-server.