Add Open API Spec

[daniel-orlov]

Is your feature request related to a problem? Please describe.
The server API lacks proper documentation and a standardized way to define its endpoints, request/response formats, and authentication requirements. This makes it challenging for developers to understand and interact with the API effectively.

Describe the solution you'd like
I would like to request the addition of an OpenAPI Specification (formerly known as Swagger) for the server API. By providing an OpenAPI Spec, we can describe the API's capabilities in a machine-readable format, including details on each endpoint, the expected input parameters, possible responses, authentication methods, and other relevant information. This will not only improve the API's documentation but also enable developers to generate client libraries, perform automated testing, and explore the API using various tools.

Describe alternatives you've considered
There are some alternatives to the OpenAPI Spec, such as API Blueprint and RAML, but OpenAPI has gained widespread adoption and has a rich ecosystem of tools and support. Without a standardized API specification, developers may have to rely on ad-hoc documentation or struggle with understanding the API through trial and error.

Additional context
Let's use the latest OAS, if possible