[FEATURE] dnf modules compatibility

[fedelebrero]

It currently supports centos8 / rhel8 but with some limitations.

The formula does not have the ability to deactivate / activate dnf modules, which would be great for example to use it with CentOS AppStream or remi-repo: https://blog.remirepo.net/post/2019/12/03/Install-PHP-7.4-on-CentOS-RHEL-or-Fedora

Regards,

[myii]

Transferred from #12.