HTML formatted report

Description

Added trampoline to CI pipeline, and added class to generate HTML formatted report.

Changes

• Modified /api/v1/assignment/{aid}/submission/{sid} endpoint to accept optional parameter format. When ?format=html is passed to this endpoint, the HTML formatted report object is returned.
• Updated documentation to reflect changes

Additions

• Added HtmlReportGenerator class, which can generate a readable HTML report from a report object.

Test and Review

To be filled in by the reviewers

• All of the methods are commented to expectation

• The methods are tested to satisfaction

• There are no unnecessary files present in the MR

• The continuous integration has no problems with the MR

• The MR is filled in as requested (including labels, milestones, and reviewers)

• The documentation is up-to-date

• All nullable parameters are marked as such

Closes #135 (closed)