Bootdisk and discovery kexec broken for EL 8.3

Dracut in PXE images for RHEL 8.3 no longer accepts hardware type prefix in the BOOTIF kernel command line parameter. Foreman PXE/Grub2 templates adds BOOTIF with the prefix (e.g. BOOTIF=00-AA-BB-CC-DD-EE-FF) which leads to failure because NIC is not properly initialized. For PXELinux IPAPPEND 2 statement must be also removed because it automatically generates and appends BOOTIF statement with the prefix.

We need to implement a workaround in PXELinux, iPXE and Grub templates for this specifically for EL 8.3 or EL 8.3+ if this turns out to be expected behavior.

I am working on a workaround, this is gonna be a templates change and we will likely backport this into 2.3 and 2.2 versions. All Foreman versions are affected unfortunately, make a template change if you need to provision EL 8.3 systems.