better support for CentOS; reboot if installer was unable to reload kernel module

[xy2]

Differences by OS family simplified and clarified. Role didn't work for me on CentOS as-is.

Kernel headers packages are removed quickly, so installation may fail if kernel is not updated. Added flag for it.

Detect if VM is still running old version of module and reboot.

[PeterMosmans]

Thanks for your additions! I'll be testing the PR shortly on other OS flavors...