Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/build/docker/grafana/provisioning/datasources/prometheus.yml

@@ -0,0 +1,11 @@
+apiVersion: 1
+
+datasources:
+  - name: Prometheus
+    type: 'prometheus'
+    access: 'proxy'
+    orgId: 1
+    url: 'http://prometheus:9090'
+    isDefault: true
+    version: 1
+    editable: false