Add first report

[pheyvaer]

Once a challenge is completed there is no quick/easy way to find all information about a challenge. The only thing that people can look at is the issue of the challenge, but that can be hard and a lot of work to completely go through and understand. With this pull request, I propose to add a report per complete challenge. That way people who are interested in a specific challenge only need to the read the report.

The report can also contain extra information that is not in the issue:

• Future work, such as ideas for future research and challenges.
• Follow-up actions, such as adding helper code from the solution of the challenge to an existing tool/library/technology like Comunica or SolidLabLib.js.

In this pull request I added a report for one challenge and a template for future reports.

[pheyvaer]

Katrien reviewed this and approves.