[Feature] Added more methods

[jantinnerezo]

What's added?

• Added allowOutsideClick method with boolean type parameter "allowed" default is true
• Added allowEscapeKey method with boolean type parameter "allowed" default is true
• Allow null parameter type on timer method

Usage

For example, if you don't want to close alert on outside click, escape key and disable auto close.

LivewireAlert::question()
  ->title("Are you sure do want to approve proposal?")
  ->allowOutsideClick(false) // new method
  ->allowEscapeKey(false) // new method
  ->timer(null) // You can pass null now instead of only integer and that disables auto closing