Publish a RedHat UBI image

[MikeGoldsmith]

Is your feature request related to a problem? Please describe.
It is desirable to have a published RedHat based image of the agent. It is preferable to use a UBI-based image for containers that run on OpenShift.

Example PR that uses UBI-minimal:

• maint: switch published image base to use rhel/ubi-minimal #291

Publishing a RedHat based image would not replace the current image distribution. Ideally, we would publish multiple images and users can select the one that best suits their needs.

Items to consider:

• Distributable image is based on UBI
• The image is published in addition to the current Ubuntu image
• The release process builds, tests and publishes all the images