Identify docker hub pushes for non-released code as 'alpha'
Openfire builds that are not a release typically identify themselves as 'alpha'. The corresponding Docker images could do the same, which would reduce confusion.
Docker publishing only after all tests succeed.
Previously, only the Smack test outcome was taken into account (as the others were not stable). Smack's output was not very stable either, which made this seemingly an arbitrary choice. The resulting flow diagram might have added more confusion than worked around actual issues?