Simplify Selenium reporting configuration

[Galad]

Provide a single method for configuring Selenium reporting (text + XML / HTML report + screenshots).

var actor = new Actor("John").WithSeleniumReporting(
     "C:\screenshots", 
     "Screenshot_{0:00}",
     out var reporter,
     new DebugObserver(),
     new ConsoleObserver()
     );

The signature of the method would be

public Actor WithSeleniumReporting(this Actor actor,
                                   string screenshotDirectory,
                                   string screenshotNameFormat,
                                   out ISeleniumReporter reporter,
                                   params IObserver<string>[] textOutputObservers);

The newly introduced interface would be a facade for accessing the report and saving the screenshots

public interface ISeleniumReporter
{
    XDocument GetXmlReport();
    string GetHtmlReport();
    void SaveScreenshots();
}