Create an RFC Discussion (/olrfc)

When the user runs /olrfc, or asks to post/create an RFC, guide them through writing a short, high-altitude RFC and posting it to mitodl/hq as a GitHub Discussion in the RFC category.

What an RFC is for

An RFC exists to get a team of busy people to agree on what problem we're solving, roughly how we intend to solve it, and what that commits us to. It is a decision document, not a design document.

The implementation detail follows later, as a spec opened against the target repositories. Anything a reader does not need in order to say "yes, go do that" belongs in the spec — not here.