Init fails if go.mod exists. Removed commands that prevented this.
If go init is to be re-run, then the go.mod needs to be manually
removed, as it should be.
The docker build fails if the go.sums file needs to be updated.
In the original article, this required a local go install to run
the metadata update commands.
This change updates the Makefile and documentation to add two new
utility targets
sjc