RHOAIENG-72: Specify numeric UID in Dockerfiles

This resolves the

```
Error: container has runAsNonRoot and image has non-numeric user (rhods), cannot verify user is non-root
```

issue.

OpenShift (by default)
runs images under a random user id and the root user group.

See https://access.redhat.com/documentation/cn/openshift_container_platform/4.15/html/images/creating-images#use-uid_create-images

components/notebook-controller/Dockerfile

@@ -57,6 +57,6 @@ COPY --from=builder /workspace/notebook-controller/bin/manager /manager
 COPY --from=builder /workspace/notebook-controller/third_party/license.txt third_party/license.txt
 
 ## Switch to a non-root user
-USER rhods
+USER 1001:0
 
 ENTRYPOINT [ "/manager" ]

components/odh-notebook-controller/Dockerfile

@@ -55,6 +55,6 @@ COPY --from=builder /workspace/odh-notebook-controller/bin/manager /manager
 COPY --from=builder /workspace/odh-notebook-controller/third_party/license.txt third_party/license.txt
 
 ## Switch to a non-root user
-USER rhods
+USER 1001:0
 
 ENTRYPOINT [ "/manager" ]