Syndesis CR might need configurable tag for upgrade image

For Fuse 7.4, the tag for the upgrade image is hardcoded inside the operator image, in /conf/syndesis-template.yaml.

This was to ensure that the upgrade pod is always the same tag as the operator image, but that's not always the case for product builds, e.g. currently the operator tag is 1.4-14 and the upgrade tag is 1.4-11.

It also means that CVE rebuilds cannot be automated using freshmaker, since there's a semi-automatic step required that changes the upgrade image tag inside the operator image (please correct me if I'm wrong here).

I've been told that we want to have automated CVE rebuilds with freshmaker for 7.5, so we should remove the hardcoded tag value inside the operator image (now resides in /conf/config.yaml).

One way of doing it is adding a tag option in the syndesis CR and having the operator read that.

cc opiske lgarciaac rhn-support-hbraun