Add `appointment_details_for_service` to routes.js
Add `appointment_details_for_service` to routes.js

This takes the service name eg `diabetes-foot-check` and returns some
context which we will put into the subsequent appointment and
confirmation pages.

nhsalpha/nhs_prototype_kit,nhsalpha/nhs_prototype_kit,nhsalpha/nhs_prototype_kit,bencullimore/nhsers,st3v3nhunt/prototype-ers,st3v3nhunt/prototype-ers,st3v3nhunt/prototype-ers,nhsalpha/nhs_prototype_kit,st3v3nhunt/prototype-ers,bencullimore/nhsers,bencullimore/nhsers,bencullimore/nhsers