The splitting of AndroidDriver and IOSDriver

[TikhomirovSergey]

Description

AndroidDriver should be separated into AndroidUIAutomatorDriver and SelendroidDriver.
IOSDriver should be splitted into IOSAutomationDriver and IOSXCUITDriver.

[TikhomirovSergey]

#143

[saikrishna321]

@TikhomirovSergey should this be still open ?

[SrinivasanTarget]

As we deprecated legacy drivers officially at server end, we can close this.