Create double_click utility method

[OSRS-B0b]

I used this online tool to measure my average double click speed. You can click once then click again and it'll show you the time between clicks. You'll need to click the reset button between clicks. I personally averaged between 0.15 seconds and 0.3 seconds between clicks in a double click.

I tested the new double_click method using the same approach and adjusted the sleep between clicks until the it was roughly the same as my own double click speed.