AS: An operator wishing to deploy ONAP

I WANT TO: be able to have access to multi-cpu architecture portal-apps container image

SO THAT: I can choose among several hardware and cloud providers that fit my requirements and needs.

For each container image delivered by the Portal project, modify the Dockerfile, or use a template if available, in order to:

-Specify a base image that is cpu platform agnostic (i.e. Alpine Linux)
-If necessary, modify the Dockerfile instructions to build on at least Intel and arm cpu architectures
-Verify that the container images pushed to the ONAP Docker registry contain layers for at least Intel and arm cpu architectures.