Razor server needs to perform locale negotiation

When the Razor server receives a request from the API, it needs to determine the most appropriate locale based on the user's wishes expressed in the Accept-Language header and the available locales in locales/ so that any human-readable messages in the response can be properly translated by fast_gettext.

AFAICT, all the plumbing to do the translating are in the code already, we are just missing the code to actually tell fast_gettext what locale to use based on the user's request.

In Scope

• Read the client's locale preference (Accept-Language header) in all requests
• Use this locale to look up gettext translations for messages, if any exist yet.