Add Appium support

[wurzelkuchen]

For a good coverage of browser based frontend tests, mobile browser support would be great and is requested by a customer of mine.
There is a way to include appium (which works well with saucelabs).
See https://github.com/selenide-examples/selenide-appium for further information. This example however seems not to work with the current neodymium version, which is probably due to incompatible versions of selenium and appium.

[occupant23]

ready for test

[wurzelkuchen]

tested it, works well with saucelabs and android/ios emulators