Switch to a token for billingName & address

Switch to a token for billingName & address

This adds the token to the contribution entity & updates the event receipts
to use it (including the ones we are gonna kill cos
it was a simple replace).

Note I updated the format function to
access apiv4 style label fields & let the
chips fall where they may re event & county
(ie you probably wouldn't set county but if you
did AND your address format is configured to show it who are
we to say otherwise)