Adds rake task and yml file

 * First pass implementation
 * Removal of this first pass as it wasn't good enough

lib/tasks/gitlab/metrics.rake

 # frozen_string_literal: true
 
+namespace :metrics do
+  desc "GitLab | Metrics | Setup development metrics"
+  task :setup_development_metrics, [:project_id] => :gitlab_environment do |_, args|
+    shared_multi_metrics_attributes = {
+      title: 'Memory multi metric',
+      y_label: 'Memory (GiB)',
+      project_id: args[:project_id],
+      unit: 'GiB',
+      group: 'system'
+    }
+    PrometheusMetric.find_or_create_by(
+      **shared_multi_metrics_attributes,
+      identifier: 'additional_system_metrics_container_memory_usage',
+      legend: 'Usage (GiB)',
+      query: 'avg(sum(container_memory_usage_bytes{id="/"}) by (job)) without (job) / 2^30'
+    )
+    PrometheusMetric.find_or_create_by(
+      **shared_multi_metrics_attributes,
+      identifier: 'additional_system_metrics_kube_node_status_capacity_memory_bytes',
+      query: 'sum(kube_node_status_capacity_memory_bytes{kubernetes_namespace="gitlab-managed-apps"})/2^30',
+      legend: 'Capacity (GiB)'
+    )
+    PrometheusMetric.find_or_create_by(
+      **shared_multi_metrics_attributes,
+      identifier: 'additional_system_metrics_kube_pod_container_resource_requests_memory_bytes',
+      query: 'sum(kube_pod_container_resource_requests_memory_bytes{kubernetes_namespace="gitlab-managed-apps"})/2^30',
+      legend: 'Requested (GiB)'
+    )
+  end
+end
+
 namespace :metrics do
   desc "GitLab | Metrics | Setup common metrics"
   task setup_common_metrics: :gitlab_environment do