Description of problem: For OCP 4.15 and 4.16, we're only supporting OSP 17.1 as the underlying platform, as seen in the support matrix. However the UPI docs recommend pulling softwares from the openstack-16-tools-for-rhel-8-x86_64-rpms repository.

We should update the instructions to match the supported platform.

Additionally, QE will need to update their tests to follow downstream installation method, which we'll track with SOSQE-1869.