font-size-adjust is still a flag-enabled feature in Chrome 77, and
doesn't have widespread support across browsers. So instead this uses
font-size to make the text large enough.
Ref T690
This uses the Invite fetched from the database to explain a bit more
about how the invite URL expires. It also reduces some space around the
input box.
Ref T690
this adds a new page with instructions for sharing user invites
if a user clicks the link for one of their own invite codes they are
directed to a page with clear instructions for it's use.
if a user clicks another users link they are redirectec to their account
settings witha flash telling them they do not need to register.
