Azos.Client.Http - options for HTTP2 etc.. usage

[zhabis]

Related: #722

See: https://www.siakabaro.com/use-http-2-with-httpclient-in-net-6-0/

  HttpClient myHttpClient = new HttpClient
    {
        DefaultRequestVersion = HttpVersion.Version20,
        DefaultVersionPolicy = HttpVersionPolicy.RequestVersionOrLower
    };