Add support for RHEL 10 and compatible clones

Notes:

Rspamd and its dependencies don't exist as packages for EL10 at the moment and would require manual installation or manual packaging.

AWStats doesn't exist in EPEL 10, only GoAccess exists. Webalizer is dead software since many years, so who cares.

The rest of the software stack that ISPConfig utilizes does exist for EL10 though.