def _handle_alert has hard coded 5 seconds of wait, but must use selenium timeout value #917

Hi

There is hard corded 5 seconds waiting time in keywords for browser alerts.
For example keyword Confirm action, if there is no alert will take 5 second until will be failed. The same for Alert should be present, etc. The main problem: it slows down tests.

What I suggest:
this keywords must use Selenium Timeout which is defined within importing library or by Set Selenium Timeout keyword.

Example of code from keywords/alert.py