I think that a server with mod_security is almost unbreakable, and my request is a panel for configure mod_security from ISPConfig?
No, it simply means that no one did it yet. Not more and not less. You can configure it already by using the directive snippts feature or the apache directives field.
If you like to contribute to ispconfig, then please sign up for a git account here https://git.ispconfig.org/ then let me know your username so that I can grant the account permissions to for ISPConfig on the git server and then you can start developing it. To get the code into the main ispconfig line, make a merge request when your code is finished.
Yes, I'd like to add several things, but first I have to tester. Do you have a official docker with ISPConfig?
No, and docker is not really suitable for a control panel like ISPConfig as ispconfig has to edit many config files and system users, so if you would have a docker image then you would have to define many files and folders to be stored outside of the docker system. But there is someone who has build one, maybe it works for you: https://www.howtoforge.com/community/threads/docker-ispconfig.70099/
I'll do the development in a VM on my desktop. I use vmware but virtualbox should be fine as well. This way you can do a snapshot and return to the original setup at any time to test it on a clean install again.