Revert "Integrate MON and Grafana"

This reverts commit 87b620ac.

Reason for revert: Grafana-k8s requires Juju 3.1 and we are not ready
to change Juju versions at this time

Change-Id: I645f1a8bd71b48f5d139420dbe7d879c88c6a2c7
Signed-off-by: Mark Beierl <mark.beierl@canonical.com>