Move link creation to fastapi dependency

[geospatial-jeff]

Right now there is a starlette request object that is injected into each endpoint and the user is responsible for creating links. The starlette request object is available from within a fastapi dependency, so it may be easier to create links inside a dependency and inject these links into each endpoint.

[geospatial-jeff]

This is a good way to encapsulate all of the logic required to generate base URL for links including forwarding headers, router prefixes etc.