docs: add releases discovery

Description

This MR adds a discovery for release cycles and release management.

Supporting information

resolves #37 (closed)

Testing instructions

Steps to test the changes:

1. Checkout the changes
2. Setup a virtualenv with mkdocs installed
3. Run mkdocs serve
4. Proofread

Dependencies

N/A

Screenshots

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]((https://gitlab.com/opencraft/dev/grove/-/blob/main/tools-container/ci_vars.yml) is updated
• The grove-template repository is updated

Additional context

N/A