Add a --skip-reboot flag to spin maintain

[jaydrogers]

👉 Describe the problem

The logic to run a reboot depends on if the system needs to reboot. The control of the reboot should allowed to be dictated by the sysadmin.

👥 Problem evidence & reach

https://www.reddit.com/r/laravel/comments/1hhumfe/comment/m2untmc/

🥰 Describe the "impact" on users?

This can be frustrating if you want to run updates, but do not want your server to reboot.

🏆 How to solve this problem

Add a --skip-reboot flag to spin maintain

If this flag is set, the server WILL NOT reboot, regardless if the system is marked that it needs a reboot or not.

💯 How do we validate the problem is solved?

1. Run spin maintain --skip-reboot
2. Updates should run
3. The system should need a reboot after an upgrade, but it should NOT reboot because the --skip-reboot is set