Add inference api docs

[andrewm4894]

• add inference api docs to docs site.
• add instructions for manually updating them.
• add title to inference server fast api app so it shows up properly in the docs.

Ends up looking like below where docusaurus just handles the multiple *-openapi.json pretty well

[andrewm4894]

Planning on making another go at trying to automate the update of the api docs (via the api contract tests workflow) too. Will try get to that next.