feat: add support for the dayz config file config setting

[danstis]

As a DayZ server admin,
I want the library to surface the new cfg file setting,
so I can query it.

setting:

"enableCfgGameplayFile": "0"

[danstis]

The library already has the ability to upload and download files, so the content can already be handled.
Still need to add the config item.