feat: add the management API (readonly). Generate the OpenAPI spec

[Angelmmiguel]

All the context is available in #153

Introduce a management API for Wasm Workers Server. For now, this API has only two endpoints:

• /_api/v0/workers: returns all the workers in the current project.
• /_api/v0/workers/{id}: returns the details of a worker like its configuration.

Currently, workers doesn't have any associated identifier (ID). I'm generating it by computing the SHA256 of the {project_root}/{file} path.

API Implementation

The API is split into two crates:

• api-manage: contains the source code of the API. It includes the models and the handlers. It exposes a method to configure an app service with these new methods. By default, wws doesn't enable the management API.
• api-manage-openapi: renders the OpenAPI specification from the api-manage and expose it. We will reuse this crate in the future to generate the CLI client in Rust (See Local panel to manage the current project #153).

To define the OpenAPI spec, I'm using utoipa, an amazing crate to generate OpenAPI specifications from rust web frameworks like Actix. I only need to add annotations to the methods and models and it generates all the information.

Note that utoipa exposes the OpenAPI spec as an HTTP endpoint, but we don't want to expose it for now. That's the reason we're using the api-manage-openapi spec crate to generate it into a file. The process is done in the build.rs file of that crate.

[ereslibre]

Super! LGTM 👏