Make required changes to run AKS, EKS and GKE regression jobs with latest build changes

Build process for operator related images has changed - details can be found here:

https://hub.internal.couchbase.com/confluence/display/CR/Docker+naming+conventions+for+Autonomous+Operator+pre-GA+builds
https://hub.internal.couchbase.com/confluence/display/CR/Grand+Unified+Build+and+Release+Process+for+Operator

Server and Sync gateway images will still be in docker hub

TL;DR - we need support in test framework to create secrets and pull images from both gitlab and docker hub accounts - Simon has a patch set already for this http://review.couchbase.org/c/couchbase-operator/+/130219 - we also need some jenkins changes to be made:

1. Docker hub and Gitlab creds created in QE jenkins as Global creds under System
2. Use these creds along with the changes made by Simon to get our regular regression working against EKS, AKS and GKE
3. This is applicable only for 2.1.x - we should consider cloning the current 2.x.x jobs and create new ones for 2.1.x