Decide what to do with ppc64le support
Current ppc64le builder is inoperative. We either need to get builder back up or drop the architecture. Once 21.08 release is done, ppc64le will become an outlier which cannot be built with previous release's PreBootstrap image. We also don't have a functioning Docker image for the architecture anymore.
Either get a builder or remove support from master completely.
There is a resolution to ppc64le problem