Added custom dashboard

.gitlab/dashboards/single_stats_custom_dashboard.yml

+dashboard: 'Metrics Dev'
+panel_groups:
+  - group: 'Memory'
+    panels:
+      - title: Prometheus
+        type: single-stat
+        metrics:
+          - id: single_stat_offset
+            query: 'max(go_memstats_alloc_bytes{job="prometheus"})'
+            unit: bytes
+            label: "Max"
+            metric_id: 3000