repo: Rename compose templates to compose.yaml.jinja

It is a short, concicse name for the compose (and one of the ways that
docker officially recommends to name the files), and jinja is the
careful recommendation of the jinja docs.

https://jinja.palletsprojects.com/en/stable/templates/#template-file-extension

roles/grocy/templates/docker-compose.yaml.j2

@@ -1,43 +0,0 @@
-services:
-  grocy:
-    container_name: grocy
-    image: lscr.io/linuxserver/grocy:latest
-    networks:
-      - caddy
-    environment:
-      - PUID={{ stack_grocy_puid }}
-      - PGID={{ stack_grocy_pgid }}
-      - TZ={{ stack_grocy_tz }}
-      - UMASK_SET={{ stack_grocy_umask_set }}
-    volumes:
-      - "{{ arrstack_env_dir }}/config/grocy:/config"
-    restart: unless-stopped
-    labels:
-      caddy: "{{ stack_grocy_subdomain }}"
-      caddy.reverse_proxy: "{{ '{{' }}upstreams 80{{ '}}'}}"
-
-{% if restic_enable is not undefined and not false and stack_grocy_restic_enable is not undefined and not false %}
-  backup:
-    image: mazzolino/restic
-    hostname: "{{ ansible_hostname }}"
-    environment:
-      TZ: "{{ restic_tz }}"
-      SKIP_INIT: true
-      BACKUP_CRON: "{{ stack_grocy_restic_cron }}"
-      RESTIC_REPOSITORY: "{{ restic_repo }}"
-      RESTIC_PASSWORD: "{{ restic_pass }}"
-      AWS_ACCESS_KEY_ID: "{{ restic_s3_key }}"
-      AWS_SECRET_ACCESS_KEY: "{{ restic_s3_secret }}"
-      RESTIC_BACKUP_ARGS: >-
-        --tag grocy
-      RESTIC_BACKUP_SOURCES: "/backup"
-    volumes:
-{% if restic_repo is regex('^/.+') %}
-      - "{{ restic_repo }}:{{ restic_repo }}"
-{% endif %}
-      - "{{ stack_grocy_env_dir }}:/backup/{{ stack_grocy_env_dir }}"
-{% endif %}
-
-networks:
-  caddy:
-    external: true