Use Nexus as a proxy for pulling images from Dockerhub

[BraisVQ]

Is your feature request related to a problem? Please describe.
We have experienced pull rate limits from time to time when pulling images from DockerHub on certain Quickstarters.

Describe the solution you'd like
Some time ago we have added a proxy to dockerhub and github images in Nexus so to avoid this issues we should use this nexus proxy instead

Describe alternatives you've considered
N/A

Additional context
I guess we need to adapt a bit the Shared library on the provisioning pipeline and make the quickstarters point to the nexus instance proxy repository

To Do:

• Add Openshift appDomain in Quickstarter Pipeline context ods-jenkins-shared-library#1078
• Make Quickstarters use Nexus Docker proxy instead of DockerHub #1000

[renedupont]

The following is a duplicate: #811
This as well: #526