Image is built multiple times during release

[pablochacin]

After #98 and #116 the images are built multiple times in the release workflow to publish them using different tags to multiple repositories, depending on conditions such as if it is a push to master, a release and if the release is a release candidate.

A more efficient process would be to generate all the required tags according to the rules described above in one step and use those tags in a single build and publish step.