**What this PR does / why we need it**:

This PR fixes a few small things with the helm chart:

* After upgrading to the new minio chart, the subvalues for that chart
were not correctly changed to the new values for `rootUser` and
`rootPassword`
* The default replica count for the new minio chart is 16, which seems a
little much for our needs.
* The `grafana-token` created by the tokengen job was meant to be used
when configuring the GEL plugin, but it was not working, so I removed
it.