Implement a UUID in powerstrip requests

[aanm]

I would like to see some sort of UUID in the powerstrip-requests for the pre-post-hooks messages.
That would be a possible way to have adapters to communicate with each other outside powerstrip.

POST /adapter HTTP/1.1
Content-type: application/json
Content-length: ...
{
    PowerstripProtocolVersion: 1,
    Type: "pre-hook",
    Uuid: "de305d54-75b4-431b-adb2-eb6b9e546013",
    ClientRequest: {
        Method: "POST",
        Request: "/v1.16/container/create",
        Body: "{ ... }" or null
    }
}
POST /adapter HTTP/1.1
Content-type: application/json
Content-length: ...

The adapter response wouldn't be changed
For the post-hook the message would be similar:

POST /adapter HTTP/1.1

{
    PowerstripProtocolVersion: 1,
    Type: "post-hook",
    Uuid: "de305d54-75b4-431b-adb2-eb6b9e546013",
    ClientRequest: {
        Method: "POST",
        Request: "/v1.16/containers/create",
        Body: "{ ... }"
    }
    ServerResponse: {
        ContentType: "text/plain",
        Body: "{ ... }" response string
                        or null (if it was a GET request),
        Code: 404
    }
}