chore: Make TrinoCatalog.spec.connector.iceberg.metastore optional

[sbernauer]

Description

Note: For CRD change see deploy/helm/trino-operator/crds/crds.yaml.

Motivation:

As the Hive metastore connection is currently mandatory, this blocks users from using a Iceberg REST catalog.
I want to do exactly that in the nifi-operator integration tests.
We also had questions for exactly this problem on Discord and problems during the last on-site.

This PR simply makes the field optional, that's it 😅

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

Author

• Changes are OpenShift compatible
• CRD changes approved
• CRD documentation for all fields, following the style guide.
• Helm chart can be installed and deployed operator works
• Integration tests passed (for non trivial changes)
• Changes need to be "offline" compatible
• Links to generated (nightly) docs added
• Release note snippet added

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
• Proper release label has been added
• Links to generated (nightly) docs added
• Release note snippet added
• Add type/deprecation label & add to the deprecation schedule
• Add type/experimental label & add to the experimental features tracker

[NickLarsenNZ]

I see no problem with this. We did a similar thing when NiFi no longer needed a ZooKeeper cluster.