Remove grype from container scanning

What does this MR do?

Changes from :

• Remove grype from docs, licenses, version files... (!3001 - merged)
• Remove grype from script, rake tasks and rspec ... (!3002 - merged)

and

• removes SCANNER env var from wherever is possible (19092fee)

What are the relevant issue numbers?

Remove Grype from Container Scanning (gitlab-org/gitlab#439165 - closed)

Refactor Container Scanning to address the sing... (gitlab-org/gitlab#456927)

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for GitLab EE, if necessary
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Job definition updated, if necessary
  • Auto-DevOps template
  • Job definition example
  • CI Templates
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer