Create license page

[isaacvetter]

Link from footer, intended to deprecrate PR #480

[jmandel]

I like the content on the license page -- thanks for these updates!

I still think it's too hard to find, with a small black icon on a small black strip at the very bottom of the page. Even the main FHIR spec includes a link to the license front and center of the home page:

and has (slightly) better contrast on the link, and doesn't bury it so far below a think black footer:

My preference would be to keep a menu item like "License and Logo" in the nav bar, for discoverability. (I'm not just saying this because I want to push legal language on everyone; I worry taht the tiny link at the bottom will be actively hard to find for people who are looking.)

[isaacvetter]

@jmandel - what's needed to close or move this issue forward?