Create Containerfile.operator files in preparation to move to RHTAP

[subbarao-meduri]

• I added CHANGELOG entry for this change.
• Change is not relevant to the end user.

Changes

Verification

[douglascamata]

@subbarao-meduri how will we maintain this Makefile? What do we have to do when it diverges from upstream? Can we not duplicate everything but only extend the make targets that we need?

[subbarao-meduri]

@douglascamata I re-did the new Makefile targets to only override specific targets while including original Makefile. This should make it easier to maintain. Please review.

[douglascamata]

/lgtm

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: douglascamata, subbarao-meduri

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [douglascamata,subbarao-meduri]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment