Add starter tasks section to docs

One initiative we are working towards is to make contributing at the OCF more accessible and to provide organized activities for new staff to participate in for the first few weeks of the semester.

While we figure out a more permanent home for the starter tasks and projects currently being developed by internalcomm and decalcomm, here is a new section in the "getting involved" page that we can direct new staff to when they ask how they can start contributing.