Stop pushing images for draft PRs

[donaldgray]

Should we update GH "Build, Test & Publish" action to not push the final image for draft PRs? Are docker images for draft PRs used?

Often a draft PR is opened early in the development process and receives frequent updates. This will result in a lot of images being build and stored that are never used.

Similarly - should we run Sonar checks for draft PRs? (seems unnecessary)