Adds a new endpoint (`/spec`) which returns a the specification of the
API in Swagger-formatted JSON.
This means we will have something to point frontends at, so we can
evaluate which ones we like.
Right now it’s all hand-defined. If we were consistent about our use of
Marshmallow we could generated the spec from the Marshmallow schemas.
- adds a base client
- adds a notifications client
These do not proxy onto genuine methods. This pull request is the basic implication of the API Client. Still needs a few things before is ready, notably proper logging and actual API endpoints to hook into.
Basic premise is to deliver the JWT tokens required for Notify API authentication so we can discuss the implementation/premise.
