Add influxdb provisioning for Grafana

This will provide access to Home Assistant and Proxmox metrics.

core/metrics/grafana/provisioning/datasources/influxdb.yml

@@ -0,0 +1,21 @@
+---
+apiVersion: 1
+
+datasources:
+  - name: Home Assistant metrics
+    type: influxdb
+    access: proxy
+    orgId: 1
+    url: http://192.168.2.75:8086
+    database: hass
+    isDefault: false
+    version: 1
+ 
+  - name: Proxmox stats
+    type: influxdb
+    access: proxy
+    orgId: 1
+    url: http://192.168.2.75:8086
+    database: proxmox
+    isDefault: false
+    version: 1