Add HTTP reporter

Add HTTP reporter

The reporter can be configured using the following:

```
% Define http client callback
Client = fun(Url, Method, Headers, Body, ReporterOptions) ->
    ibrowse:send_req(Url, Headers, Method, Body, [])
end.

[
    {protocol, http},
    {endpoint, "http://127.0.0.1:14268"},
    {http_client, HttpClient}
]
```