Adjusted user creation in UBI 8 image

[bradfordcp]

Added chown and chmod flags to COPY commands
Added update step to UBI 8
Updated UBI 8 to point at Docker Hub container
Removed UBI 7

[burmanm]

@bradfordcp You had something to check still last time we talked, is this fine now?

[bradfordcp]

The latest version works in my testing. I'm a little iffy on setting the definitions directory to 777, but omitting that leads to weird errors when the config builder is scanning definitions. The USER setting in the Dockerfile isn't always being respected. Do you think this is an issue given these files are all templates?

[bradfordcp]

Setting the execute bit on the files wasn't sitting right with me. I refactored the ubi builder image to set the bit appropriately on directories and then copied those definitions in. Tested with the latest k8ssandra-operator in Helm and the following modified K8ssandraCluster

apiVersion: k8ssandra.io/v1alpha1
kind: K8ssandraCluster
metadata:
    name: foo
spec:
    auth: false
    cassandra:
        serverType: dse
        serverVersion: 6.8.43
        initContainers:
            - name: server-config-init
              image: bradfordcpdstx/cass-config-builder:1.0.9-dev-ubi-5

Note the named repo is deleted