Build job posting form

[GA]

Build form to serve as test for job posting tool

Blocked at least partially by #55 (Prompts)
Not blocked by #61 (Design)

• @pacarole and @antislice need to discuss extending existing tool vs. greenfield (aka is this still a fork of joblint)

Can be split up further if some prompts are more intensive than others.

This issue originally created by pacarole as https://api.github.com/repos/codeforamerica/nola-2016-fellows/issues/56.