Git：舞台，现场，开发网络环境中的“子项目”差异化

I have a complex web project template where files can be divided into three categories. Firstly, settings related files that should be unique on each server, is not updated frequently, but would be nice to have it in version control. Secondly, development files which is the actual files coded by developers and is unique per project and is the main files to be version controlled. And finally, user generated content which would be mostly test data on Stage and Development environment, but proper data on a Live server, and ideally should also be version controlled.I have a complex web project template where fil