Astral Wallaby

Add openapi spec merge method (#67)

**What**
- Add new generator that merges a directory containing OpenAPI specs
  into a base OpenAPI spec. This allows defining a base spec with
  common definitions and then merge into schemas and paths from
  other files. This allows keeping the schemas smaller which should
  make them easier to read and maintain. The small files can
  also be OpenAPI specs, which means they can also be linted
  independentyly.
- Our current Hub API is almost 10000 lines of yaml, which can be
  laggy in an editor. This is also difficult to maintain because
  the schema definitions are often so far away from where the are
  used. It is easier to open and reference several small files.
  Additionally, this should make it much easier to merge in changes
  from the datastore and profiler apis

Signed-off-by: Lucas Roesler <[email protected]>