Create notebooks highlighting PlasmaPy to be hosted on Learn Astropy

[namurphy]

One of the things we can do to raise the visibility of PlasmaPy in the astronomy community would be to create notebooks highlighting PlasmaPy which can be hosted on learn.astropy.org (i.e. astropy/astropy-tutorials#588).

Following a fantastic discussion with the Astropy Coordination Committee today, it sounds like creating and maintaining Learn Astropy is a huge amount of work, so it's unlikely we'll have the capacity within PlasmaPy to do that unless...unless we can have someone work on it full time for a while. If we want to do something similar, we should talk with them about the infrastructure so that we can avoid duplicating effort. (It sounds there is a similar notebook infrastructure setup at STScI worth looking into, maybe for JWST?)