Chore: Remove Harbor Trivy integration from Lagoon Core.

[bomoko]

This PR removes Trivy integration in core - since Harbor is no longer part of Lagoon core, and Insights has now taken the place of generating SBOM scan results.

It does the following:

• Removes the tables and code for harbor scan matches
• Deprecates calls in the GraphQL schema for the above
• Adds exceptions when these GraphQL endpoints are called
• Removes all webhook integrations and tests for Trivy payloads

Closes #3082

[tobybellwood]

This looks good to me, a neat and tidy excision of code that's no longer functional