feat: typing - compeller should enfore its own types for the API schema

[simonireilly]

Currently, the typing in compeller has been growing from a what can be made to work type specification but the actual typing needs to enforce the required format of the schema document.

Requirements

• All schemas need to be static, to allow for inference, so must use the JSONSchema type from json-schema-to-ts
• Since paths don't support ref's it should not be possible to put a ref in a path

Essentially, the document should be richly typed