Use a GH project to manage TRC workflow

[azaroth42]

In the W3C JSON-LD WG, we have found a GH Project to be useful in managing the workflow across multiple repos without going out to external similar kanban boards like waffle or trello.

I propose a similar pattern for managing the TRC workflow. The chairs and editors can keep the on-deck issues up to date and ordered, and then move them to other columns such as accepted / rejected / sent-back-for-further-work once consensus in the TRC is arrived at.