Update the proxy configuration and capabilities

[nicolasiltis]

• update method createFirefoxDriver()

  • it adds the noProxy (if they have been set in config.xml) hosts to the ffprofile
  • delete the if block : [if (capabilities != null) { return new FirefoxDriver(capabilities);}] to be able to add some capabilities.

• update createProxyCapabilities() to createProxyCapabilities(String type)

  • Instead of creating only chrome capabilities now it can create firefox capabilities aswell

• deletion of all the method related to html unit, because it isn't supported with selenium 3.12.0

• add the method getNoProxyHosts()

  • extract the NoProxy hosts from the config.xml file
  • Update to selenium 3.12.0

[stephendv1]

Thank you for the pull request! All changes looks good, except deleting the HtmlUnitDriver - could you leave this driver in as it's quite useful for testing Web APIs.