Add generic reports section and 'url' type to vulnerability details page

What does this MR do?

It adds a new section to show generic reports data on the vulnerability details page. It also adds one component (for URL report types) to illustrate how everything is working together and make this MR deployable.

Screenshots (strongly suggested)

type	capture
screenshot
recording / responsive behaviour	generic_report_section

How to test this?

1. Create a new project, give it a gitlab-ci.yml file with the following contents:

stages:
    - dast

dast:
  stage: dast 
  image: alpine:3.10.2
  script:
    - pwd
  artifacts:
    reports:
      dast: dast.json

2. Download $2092621 and add it to the project file dast.json
3. Run a pipeline, view vulnerabilities

(Thanks to @cam_swords for the instructions)

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
  • I have not included a changelog entry because _____.
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Related to #285144 (closed)