Add GitHub link in help

[rmccreath]

Describe the solution you'd like
The help section currently has contacts for Staff Development and the Data Science team. This could also include a link to the GitHub repo, in particular for raising an issue. For those who are already, and as others become, comfortable using GitHub features such as issues and collaborating, having a direct link will notify users that they are able to directly raise an issue (with template and following the code of conduct) or directly contribute to the project.

Additional context