The VRServer is not gracefully shutdown

[marcozzxx810]

How to reproduce:

1. add a `logManager.info("hello") in https://github.com/SlimeVR/SlimeVR-Server/blob/main/server/src/main/java/dev/slimevr/VRServer.java#L179

2. ./gradlew shadowJar

3. put the slimevr.jar from SlimeVR-Server\server\build\libs to the your installation file

4. The log doest has hello.

My proposal is that:

1. Tauri should send sigterm to the server
2. Then server should start the clean up process

Obstacle:

1. now the server cannot handle SIGINT, need to investigate how to do so

Already tried to put a shutdown hook in the main function, but It still cannot work. Not sure it related to gradle

[marcozzxx810]

This also create a problem of log lock is still there when the server close, but it should not have problem on user side

[ImUrX]

This was fixed by #632