fix: update Grove to work with new forum config

Description

This PR updates the Grove configuration for tutor so that it matches the new configuration. Notable changes:

• USE_SSL can now be a boolean
• Configuration parameters were added for authSource, adminDB and authMechanism (defaulting to SCRAM-SHA-1, cause it's the default auth method)

Supporting information

• https://github.com/overhangio/tutor-forum/pull/10
• https://github.com/overhangio/tutor/pull/741

Testing instructions

Steps to test the changes:

• Check the pipeline: https://gitlab.com/opencraft/devstacks/keith/grove-do/-/pipelines/710321332
• Go to https://es1.kgcluster.opencraft.hosting/
• Subscribe to a course and add a post to the discussion forum
• There should be no errors

Checklist

If any of the items below is not applicable, do not remove them, but put a check in it.

• All providers include the new feature/change
• All affected providers can provision new clusters
• Unit tests are added/updated
• Documentation is added/updated
• The TOOLS_CONTAINER_IMAGE_VERSION in ci_vars.yml is updated
• The grove-template repository is updated

Additional context

Add any other context about the merge request here.