Add variable shutdown timeouts

What does this MR do and why?

Implements variable shutdown timeouts. Some servers take longer than the fixed 60 seconds to shutdown so Crafty is forcing these servers down every time. This allows users to set (in seconds) a timeout between 1 - 5 minutes.

Implements suggestion #37 (closed)

Screenshots or screen recordings

How to set up and validate locally

Open up this branch. Change your timeout to whatever you would like. When you stop Crafty you will see Crafty counting down from the number you selected in your console.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• Have you checked this doesn't interfere/conflict/duplicate someone elses work?
• Have you fully tested your changes?
• Have you resolved any lint issues?
• Have you assigned a reviewer?
• Have you applied correct labels?