Before, single and cluster deployments were provisioned with both
Grafana datasources: single and cluster. But this resulted into a
problem: single DS didn't work for cluster and vice versa. See
https://github.com/VictoriaMetrics/VictoriaMetrics/pull/7113
This PR splits datasource file into 2 files: single and cluster. Now,
these files are separately provisioned to single and cluster deployments
correspondingly.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
