tweaks with backfill and grafana

.env.example

@@ -0,0 +1,18 @@
+# M3DB Cluster Credentials
+# ========================
+# Copy this file to .env and fill in your values
+
+# M3DB Basic Auth (coordinator API access)
+M3DB_USERNAME=<your-m3db-username>
+M3DB_PASSWORD=<your-m3db-password>
+
+# Mimir (source for backfill)
+MIMIR_USERNAME=<your-mimir-username>
+MIMIR_PASSWORD=<your-mimir-password>
+
+# Grafana Admin
+GRAFANA_ADMIN_PASSWORD=<your-grafana-admin-password>
+
+# M3DB Basic Auth (htpasswd base64)
+# Generate with: echo -n "username:password" | base64
+M3DB_HTPASSWD_B64=<base64-encoded-htpasswd>