Add VictoriaMetrics and VictoriaLogs as own datasources

[denisgolius]

VictoriaMetrics team created two datasources for Grafana:

• https://github.com/VictoriaMetrics/grafana-datasource for VM
• https://github.com/VictoriaMetrics/victorialogs-datasource for VL
  It would be nice to have separeted datasources for these products in Nightingale because VM datasource hase full support of https://docs.victoriametrics.com/metricsql/ as well as datasource for https://docs.victoriametrics.com/victorialogs/logsql/ . The latest one is steel in progress but anyway😏

[UlricQin]

Got it, we will think about it later.