[Spike] Support Open API format from profile

[visola]

Description

Open API is the de facto format to describe REST APIs and it would be good to have an automated way to point to an Open API definition file (JSON), that would be pulled, cached and translated to an understandable format.

It should load the base server and port.

When adding a definition file to a profile, it would automatically map all the endpoints defined in there using some pattern, need to investigate more but the idea is that something like: /users/{userId}: get would become users_userid_get.

Another thing that would be useful is to have parameters automatically checked against variables. So that an endpoint that had a parameter like the following:

parameters:
  - in: query
    name: offset
    schema:
      type: integer

when called like this:

$ http +profile @users_userid_get -V offset=10

The request would be:

GET /users/{userId}?offset=10

When called with no variables, then it wouldn't do anything, like the following:

$ http +profile @users_userid_get

It would executed this:

GET /users/{userId}