feat: add celery beat deployment resources

Description

Adds the k8s manifests required to get Celery beat running in Kubernetes.

Supporting information

• https://tasks.opencraft.com/browse/SE-5642

Testing instructions

• Read through the code
• Check the pipeline: https://gitlab.com/opencraft/ops/grove-stage-digitalocean/-/jobs/2690338729
• Check that periodic tasks are running by verifying on the django admin: https://keith-cb.staging.do.opencraft.hosting/admin/django_celery_beat/periodictask/
  • You can create a superuser by running: ./kubectl exec -it -nkeith-cb lms-5df8674989-2qt2t -- python manage.py lms createsuperuser

Other

After merging, I'll bump the tools-container version.