Add unmodified template for FSA from Software Conservancy.

This document was taken from here:
http://sfconservancy.org/members/apply/conservancy-fsa-template.tex

This document was provided to NumFOCUS by the Software Conservancy
under the terms of the CC-0 waiver/license (public domain dedication -
http://creativecommons.org/publicdomain/zero/1.0), by Brad Kuhn.

We will use it as a starting point to create one for NumFOCUS.
Rename FSA template to reflect NumFOCUS.