Force GC on auto-pause to save RAM

## Problem

Auto-pause, despite saving the CPU power, does little to curb the rather enormous RAM usage a Minecraft server, especially with Forge, can impose on the system, being rather problematic for installations where Minecraft lives alongside other services like a home server. Auto-shutdown may seem like a solution, but as far as I can see, it doesn't support automatic startup on new network connections like auto-pause, so isn't considered a viable alternative.

## Proposed solution

I propose to amend this feature by forcing the JVM to perform a garbage collection before pausing. One way I found of achieving it would look something like

```sh
jcmd $(jps -l | grep forge-1.12.2-14.23.5.2860.jar | awk '{print $1}') GC.run
```

which would require the following options for the JVM to enable debugging

```
-Dcom.sun.management.jmxremote
-Dcom.sun.management.jmxremote.port=9010
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false
```

Perhaps there is a better implementation, but this serves as illustration for my proposal. This simple feature may make a great difference for many RAM-scarce homelabs.

## Alternatives considered

- Network-based auto-startup paired with existing auto-shutdown, like https://github.com/gekware/minecraft-server-hibernation.

Start by locating the auto-pause entry point and reviewing how the Minecraft server process is paused. Compare the proposed jcmd/jps/awk command with the listed JMX JVM options; done means auto-pause can trigger garbage collection reliably without breaking automatic resume.

Written by the indexing model from the issue text.