Generate request body struct (#30)

* Run all tests in the same cargo workspace

Running all the tests in the same cargo workspace allows test runners to avoid recompiling dependencies every time. This allows us to drop parallel tests which seemed to be causing OOMs.

* Doc cleanups and improvements

* Add support for public and private modules

* Generate Synthetic Body structs for serialization

To enable serialization & deserialization, we generate synthetic structs representing the request body. Currently, the serialization method returns a stub, however, in a subsequent PR, serde will be used to generate actual request bodies.

* Fix doc typo

* CR feedback