Facilitates in building OpenAPI description document by creating objects described in https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md
openapi_create(openapi = openapi_openapi_version(), info = openapi_info(),
servers = openapi_servers(), ...)openapi_openapi_version(openapi_version = "3.0.1")
openapi_info(title = "RestRserve OpenAPI", version = "1.0",
description = NULL, termsOfService = NULL, contact = openapi_contact(),
license = openapi_license())
openapi_servers(servers = list())
openapi_server(url = "/", description = NULL, variables = NULL)
openapi_contact(name = NULL, url = NULL, email = NULL)
openapi_license(name = NULL, url = NULL)