CLUB-971 - login for donation flow

This work is mostly complete for the donation flow. There are still some transition issues but that will require another ticket to fix bb_modal.js.

- refactor the templates for the login/signup for donations flow
- create a placeholders / translated strings property for use in templates
- update donation api permissions to allow anonymous and logged in donations 	refactor bb_modal to have more consistent behaviour
- allow user to edit user on order if it is in their session
- user not needed on Order
- handling transitions between donation modals CLUB-971
Is this empty mixin here so we can overwrite it in 1%?