Build Foreman Client for REX Pull Provider on SLES

[maximiliankolb]

• On EL, the golang package is called "golang"; on openSUSE and SLES, it's called "go".
• Require redhat-rpm-config for go When building the Foreman Client for REX pull mode, you have to compile go code. On EL, you can set a flag that requires the file "redhat-hardened-ld" which is part of the "redhat-rpm-config" package. See https://fedora.pkgs.org/rawhide/fedora-x86_64/redhat-rpm-config-264-1.fc40.noarch.rpm.html
• Do not use hardened linker on SLES Hardened go linker requires "redhat-rpm-config" which is not available on openSUSE and SLES systems.
• DBus package name depends on distribution
• Remove ldflags for compiling go on SLES
• Unset GO111MODULE on SLES
• Change bin path for yggdrasil on SLES

[maximiliankolb]

Hey @adamruzicka Can you please have a look at my PR?

[maximiliankolb]

Rebased to "rpm/develop" and resolved all merged conflicts.

[ekohl]

https://github.com/theforeman/foreman-packaging/pull/11116 & https://github.com/theforeman/foreman-packaging/pull/11118 were merged so closing this.