feat(header): Allow to add specific Host header

[b-viguier]

For optimization purpose, we intend to use a proxy between Php and ES in order to maintain persistent http connections opened. To do this in a common way, the http request must be addressed to the proxy, but using an Host header indicating the actual ES server to reach.

Unfortunately, Host header is not handled correctly, since the ES client already split the input url into scheme, uri… and a host header. Then, when we try to add our own host header, previous one is dropped 😕

The final url is computed in the CurlFactory of guzzle/RingPhp (deprecatde), using Core::url function, but if an url field already exist, the client use it.

The idea here is to compute the final url before to modify headers, in order to keep original host in the url.
Since url field is always computed, tests must be updated to take this new parameter into account.

[Oliboy50]

🤷

[Benoit382]

🤷‍♂️