Add a "Printable Version" link to Phortune invoices

Summary:
Ref T9309. This is a minor quality of life improvement, hopefully. We already have print CSS, just expose it more clearly.

Also, hide actions (these never seem useful?) and footers from printable versions. I opened the printable version in a new window since it now doesn't have any actions.

Test Plan:

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T9309

Differential Revision: https://secure.phabricator.com/D14045