Start "Astropy Ambassadors" and/or "help desk"

This is a break-out from a thread in #152 and some earlier coordination meetings. While [I think](https://github.com/astropy/astropy-project/issues/152#issuecomment-705042918) that issue was intended to be about some of the particulars about the python in astronomy fb group, a thread in that discussion veered in a different direction about the challenges of thinking of the fb group as sort of a "help desk" with active involvement from devs instead of a user discussion forum.

So this issue is meant for that particular discussion. A good starting point is https://github.com/astropy/astropy-project/issues/152#issuecomment-704727441 (and the responses to it in #152).

The short version is that we have discussed for a while was something like an "Astropy Ambassadors" program, which would be users who are specifically trained or at least "known-knowledgeable" who want to be representatives of Astropy in their institution/online space they prefer/etc. They would essentially be "power-users" (and maybe occasional contributors) to then no suck up a lot of the developers' time.

That idea pre-dated any funding, though. An alternative approach would be to actively hire some folks to work as a "Tier 1" help desk (as @pllim said in https://github.com/astropy/astropy-project/issues/152#issuecomment-704676677). I don't think any of our current funding can support that for very long, but it's worth considering if we could consider dedicated funding for this purpose.

An alternative middle-ground is to using some of the Moore funding to facilitate the Ambassadors program, either by paying the ambassadors for, say, the training time, or swag, or hiring someone to coordinate the program. This strikes me as a good starting point because it could also help the "user-to-contributor" pipeline since the ambassadors would likely be prime "contributor" territory.

(cc @kelle @astrofrog @pllim @bsipocz as participants in the relevant thread of #152)

Start by reading issue #152, especially comment 704727441 and its responses, along with the linked discussion in this issue. Done would mean reaching a decision on the ambassador, help-desk, or middle-ground approach and documenting an actionable program and funding plan.

Written by the indexing model from the issue text.