This change allows the BMC to install and run on centos9-stream.
centos-8 is skipped to reduce the required support matrix, centos-7
support can be removed once known OVB tooling is upgraded.
Then, pre-built image support can be restored, and also feature work
can be resumed in a modern python3 environment (such as implementing a
redfish endpoint).
Change-Id: I81565726f18d11c906ed23295d8acf5e18a9c2fe