This was introduced in 143e2272
Extra repo is enabled by default in CentOS, and is not the right repo for EL8
Instead of adding a CentOS repo to RHEL, enable the needed RHEL repos with rhsm_repository

For RHEL 7, we need the "extras" repo for container-selinux
For RHEL 8, we need the "appstream" repo for container-selinux, ipvsadm and socat

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

When clicking the link, we faced NotFound error page of the github.com.
This fixes the link to avoid that.

* Fix etcd download dest

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

* Only support Helm v3, cleanup install

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

* Expose offline install overrides in inventory

* Remove not recommended warning