Show the URLs scanned by DAST in the console

What does this MR do?

This MR adds logging to DAST so that the URLs that DAST scans are output to the console.

What are the relevant issue numbers?

This MR resolves part of issue gitlab-org/gitlab#11024 (closed)

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
  • Job definition example
  • Vendored CI Templates (also in CE)
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer