Deployment systems for Linux

My project is based on a Raspberry Pi distro - Raspbian. But I made changes to it. There are a lot of them: changes in config.txt, adding system services, installing new packages, change the image of the splash screen, etc. But every time when I need a new, "fresh" system I need to repeat all these changes. Are there some automated tools to perform this? Also, I want to supply these changes to my potential users, to make deployment of my changes easy on their side.