Embed RepoSense report to enhance use-case of WATcher

**Is your feature request related to a problem? Please describe.**
WATcher currently allows users to consume an aggregated view of issues and PRs in the relevant repository, seeing relevant issues and PRs by members in the organisation. It would also be useful for users working as a team to view code contribution. Hence, we could possibly generate a RepoSense report to also showcase the size of work associated with the issue or PR.

**Describe the solution you'd like**
Since RepoSense provides a JAR file that produces the relevant HTML/CSS/JS, perhaps a serverless function that executes the JAR file could be deployed. Subsequently, we can then embed RepoSense report using an `iframe` tag. Of course, the details are still fuzzy and can be changed.

**Describe alternatives you've considered**
We can discuss possible alternatives, this is more of a suggestion :)

No files, tests, or entry points are named. First review WATcher's existing issue and PR views, then investigate how the RepoSense JAR produces its HTML/CSS/JS report and whether a serverless function can host it for iframe embedding. Done means an agreed integration design and a working embedded RepoSense report.

Written by the indexing model from the issue text.