Support the 'Tap' command

[erezatias]

Reference - https://perfectomobile.my.salesforce.com/500D000001VAfR0?nooverride=1

Need to add the 'Tap' command to Quantum (currently supported in Selenium).
The need comes from an issue where a customer (StateFarm) needs to press on a picker wheel object and fails using the touch operation (need less duration in the 'key down' operation).
The suggested solution:
Explanation - some of the UI objects may need different touch intervals and this can vary according to element types and sometimes even device types can impact that too.
Our suggestion - replace the 'click' (touch) command with 'tap' command (as shown below) with 50 ms delay.

=======================
/**

• Convenience method for tapping the center of an element on the screen
• @param fingers
• number of fingers/appendages to tap with
• @param element
• element to tap
• @param duration
• how long between pressing down, and lifting fingers/appendages
  */
  void tap(int fingers, WebElement element, int duration);