Skip count down when players left

[Dashboy1998]

Context

• Adds a countdown function so update and reboot use the same one
• Auto update outputs a single message to the server saying it will update in N minutes whereas auto reboot outputs a message counting down N minutes.
• Resolves Auto reboot and auto update when players leave #393
• Code from Move countdown to function for auto update and auto reboot #392

Choices

• Changed to match behavioral of auto reboot.

Test instructions

Auto reboot

• Set AUTO_REBOOT_CRON_EXPRESSION close to your current time
• Set AUTO_REBOOT_ENABLED to true
• Set AUTO_REBOOT_EVEN_IF_PLAYERS_ONLINE to true
• Set AUTO_REBOOT_WARN_MINUTES to 5

Players in game and messages

Join the server and verify that the server restarts in 5 minutes after the cronjob has started and you receive messages for 5, 2, 1 minutes, and 30, 10 seconds.

Players leave game during countdown

Join the server and once the cronjob starts leave the game and verify it restarts on the minute after you left.

Auto Update

• Set UPDATE_CRON_EXPRESSION close to your current time
• Set AUTO_UPDATE_ENABLED to true
• Set AUTO_REBOOT_WARN_MINUTES to 5
• Set UPDATE_ON_BOOT to true
• After the server starts change the buildId on line 33 in the file `palworld\steamapps\appmanifest_2394010.acf`` to any other value (for example 63707356556294349890)

Players in game and messages

Join the server and verify that the server restarts in 5 minutes after the cronjob has started and you receive messages for 5, 2, 1 minutes, and 30, 10 seconds.

Players leave game during countdown

Join the server and once the cronjob starts leave the game and verify it restarts on the minute after you left.

Checklist before requesting a review

• I have performed a self-review of my code
• I've added documentation about this change to the README.
• I've not introduced breaking changes.

[thijsvanloef]

It does not seem to work, even if I enter auto reboot warn minutes, the server will shutdown instantly every time, even if players are online

[thijsvanloef]

Now it works as expected! Thanks for the contributions :D