Fix circular dependencies on k3d desployment

[salvacorts]

What this PR does / why we need it:
This PR fixes circular dependencies in the loki-distributed make target.

Special notes for your reviewer:
When running make loki-distributed the following error was prtiented:

Get "http://k3d-grafana:45629/v2/": dial tcp 127.0.0.1:45629: connect: connection refused

This is due to the loki-distributed make target depending on the prepare target which will try to push the loki image to the k3d-grafana container registry.

Problem is, that would only work if the k3d-grafana cluster is already created. Which is not since it’s created on the create_cluster.sh script which will be run after the prepare target.

Checklist

• Documentation added
• Tests updated
• Add an entry in the CHANGELOG.md about the changes.

[cyriltovena]

LGTM