Improve one time password

[DeeTheDev]

Fixes #592

Pasting code from IOS devices Keyboard pasting did not trigger the paste event, instead, it triggers the onChange event. Solution is to handle pasting through onChange similar to the handleOtpPaste function. Follow changes happened due to this solution:

• Since we have to handle 6 pasted characters in each of the 6 inputs, we set the maxLength property to 6
• Multiple characters are allowed, so we check that there are no non-digit characters, otherwise we return
• Replaced onChange event to onInput to allow immediate after the value of an element has changed; ref
• handle when an input selection carat is to the left by fetching the 0 index of the value, otherwise fetch the last index of value

Handle character deletion

• Set condition to catch when "Backspace" and "Delete" keys are triggered
• Remove current value and focus the previous input element