Add DAST properties to common report format data structures

What does this MR do?

Adds new fields to common report format data structures making it capable to hold DAST tool report artifact data.

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ee/issues/9635

Further details

Format compatibility

It's important to know that some key names and values differ from the format what we currently provide for the frontend. This is made to make the DAST report format consistent with what we already have for SAST etc.

For instance, currently, we store identifier types as all-caps. In our common library they follow "all lowercase" convention: default values, custom value example.

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