Proposal for HTML artefact visualisation.

What does this MR do?

Add a feature request to visualise an HTML artefact in a repository either in its raw or its rendered format.

What are the relevant issue numbers?

n/a

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides