pull: Add a script to scrape FSF license IDs, names, and tags

pull: Add a script to scrape FSF license IDs, names, and tags

We want to use this to lookup FSF tags associated with a given SPDX
license.  The FSF is intestested [1], but maybe not enough to maintain
their own API.  Until they do maintain their own API, stub out a mock
API on their behalf, which we can hand over to them when they're
ready for it.

[1]: https://lists.spdx.org/pipermail/spdx-legal/2017-October/002281.html
     Subject: Issues added based on this weeks Legal Call
     Date: Fri, 13 Oct 2017 10:20:33 -0700
     Message-ID: <021801d34447$9443e280$bccba780$@com>