feat: Integrate External DNS with LoadBalancer service type

[as51340]

Improvements:

• Bolt server will now get automatically set-up through our cluster-setup hook when using LoadBalancer service type both for coordinators and data instance
• Added gc.yaml as an example for GatewayClass
• Gateway will apply to data instances only if dataInstance.serviceType is not defined. Same for coordinators.

[as51340]

Tracking

• [Link to Epic/Issue]

Standard development

• Update / add chart templates, values, and NOTES.txt as needed
• Run helm lint and helm template locally against the changed chart(s)
• Verify the chart installs and upgrades cleanly on a test cluster

Labels checklist

• Add a docs label (exactly one): docs-changelog-only, docs-needed, or docs-not-needed
• Add at least one component label: memgraph, memgraph-ha, memgraph-lab, or infrastructure
• Add at least one type label: bug, feature, or infrastructure
• Assign the PR to a milestone
  • If not known, set for a later milestone

Documentation checklist

• Write a release note, including added/changed clauses
  • Bolt server will now get automatically set-up through our cluster-setup hook when using LoadBalancer service type both for coordinators and data instances. Gateway will apply to data instances only if dataInstance.serviceType is not defined. Same for coordinators. #268
  • What has changed? What does it mean for a user? What should a user do with it? [#{{PR_number}}]({{link to the PR}})
• Documentation PR link
  • Is back linked to this development PR

[github-actions]

Release note advisory

Bolt server will now get automatically set-up through our cluster-setup hook when using LoadBalancer service type both for coordinators and data instances. Gateway will apply to data instances only if dataInstance.serviceType is not defined. Same for coordinators. #268

The note is informative and the PR link matches, but it uses multiple sentences instead of the required single short sentence; please condense into one concise sentence before the PR link.