Enable displaying needs from a whitelist in prod

The hardcoding of the need IDs is only a very temporary measure while need validation
is being added to Maslow (this feature is in progress).

There is precedent for this approach in alpha projects (eg the data for the Employment Income Manual
being hardcoded within the Manuals frontend application).

https://github.gds/gds/alphagov-deployment/pull/758 needs to be merged first.