Option/flag to disable force kill on shutdown

[mustul]

• Issue: On server shutdown the managing script is killing factorio instance after 10 second, but when user is using a lot of mods and have a huge map the server is not able to save the map in 10 seconds. This causes to not save the map correctly on shutdown and the user has to manualy rename one of the autosaves to the savefile name to load the latest save. Also docker has a feature to forcefully kill a container, so if the server would be actually stuck the user can still kill the server through docker.

• OS/distribution version (command for your OS may differ):

  No LSB modules are available.
  Distributor ID: Debian
  Description:    Debian GNU/Linux 10 (buster)
  Release:        10
  Codename:       buster

• Docker version:

  Docker version 18.09.1, build 4c52b90

• Labels from container: IE:

  "Labels": {
              "org.opencontainers.image.created": "2022-01-19T22:41:08.800Z",
              "org.opencontainers.image.description": "Factiorio Headless Server",
              "org.opencontainers.image.licenses": "Apache-2.0",
              "org.opencontainers.image.revision": "5f810b294df1e44cdad04446d7175ea1ab806b60",
              "org.opencontainers.image.source": "https://github.com/goofball222/factorio",
              "org.opencontainers.image.title": "Factiorio Headless Server",
              "org.opencontainers.image.url": "https://github.com/goofball222/factorio",
              "org.opencontainers.image.vendor": "The Goofball - goofball222@gmail.com",
              "org.opencontainers.image.version": "1.1.53-Debian"
          }