feat: add preliminary code for generating OAS

* Uses @sinclair/typebox to generate both JSON Schema & TypeScript types
in one go--pretty handy

* Uses fastify-swagger to generate OAS (like in storage-api)

* Preliminary support is for /schemas only

* Includes types for POST and PATCH so no need to chase postgres-meta
source code function calls anymore :-)

* Exporting docs is done by setting PG_META_EXPORT_DOCS to
`true` (server doesn't start up with this option, this is for exporting
docs only)

Author: soedirgo