CreateRouter creates the router with the required endpoints for proxied APIs The preferred approach for new APIs is to use `addVersionedHandlers` and include the version on downstream API routes.

NewServiceList creates a new service list with the provided initialiser.

Run initialises the dependencies, proxy router, and starts the http server.

ExternalServiceList holds the initialiser and initialisation state of external services.

Init implements the Initialiser interface to initialise dependencies.

Service contains all the configs, server and clients to run the API Router.

HealthChecker defines the required methods from Healthcheck.

Initialiser defines the methods to initialise external services.