WICKET-5208 Contribute jQuery 1.x or 2.x depending on the user agent

Make it easier to extend DynamicJQueryResourceReference to be able to change the used versions of jQuery and reuse #getName() where is the logic to calculate the version.

Example:
public class CustomJQuery extends DynamicJQueryResourceReference
{
  @Override
  protected String getVersion1()
  {
    return "jquery/jquery-1.10.0.min.js";
  }

  @Override
  protected String getVersion2()
  {
    return "jquery/jquery-1.10.0.min.js";
  }
}

getJavaScriptLibrarySettings().setJQueryReference(new CustomJQuery());