Handling catalog management deletition/initial data

[marest94]

In the current "out-of-the-box" Docker Compose setup, we include initial data that creates a predefined catalog along with all necessary entities such as datasets, services, distributions, policies, etc.

If a user wants to use the system in a production environment, they will likely delete all of this predefined data and start fresh. When done through the UI, this typically begins with deleting the catalog.

In such a case, datasets and other related entities would be left "hanging" because they are no longer linked to a catalog via a proper DBRef.

After a short brainstorming session, we’ve identified three potential scenarios (so far):

1. Provide two sets of initial data: one for the default "out-of-the-box" setup with a predefined catalog and related data, and another for production use, which would be empty (i.e., no catalog or related entities), but still include roles and basic configuration.

2. Implement cascading deletion in the backend: when a catalog is deleted, automatically remove all child entities such as datasets, services, distributions, etc.

3. Allow orphaned entities and re-link later: modify backend logic to allow related entities to remain after a catalog is deleted, and provide a mechanism to re-link them to a newly created catalog when appropriate.