Add a helper to generate legacy configuration

This moves the DefaultConfig method out into a helper to generate legacy
configuration.  Passing in a config file is now required.

deploy/manifests/custom-metrics-config-map.yaml

@@ -0,0 +1,74 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: adapter-config
+  namespace: custom-metrics
+data:
+  config.yaml: |
+    rules:
+    - seriesQuery: '{__name__=~"^container_.*",container_name!="POD",namespace!="",pod_name!=""}'
+      seriesFilters: []
+      resources:
+        overrides:
+          namespace:
+            resource: namespace
+          pod_name:
+            resource: pod
+      name:
+        matches: ^container_(.*)_seconds_total$
+        as: ""
+      metricsQuery: sum(rate(<<.Series>>{<<.LabelMatchers>>,container_name!="POD"}[5m]))
+        by (<<.GroupBy>>)
+    - seriesQuery: '{__name__=~"^container_.*",container_name!="POD",namespace!="",pod_name!=""}'
+      seriesFilters:
+      - isNot: ^container_.*_seconds_total$
+      resources:
+        overrides:
+          namespace:
+            resource: namespace
+          pod_name:
+            resource: pod
+      name:
+        matches: ^container_(.*)_total$
+        as: ""
+      metricsQuery: sum(rate(<<.Series>>{<<.LabelMatchers>>,container_name!="POD"}[5m]))
+        by (<<.GroupBy>>)
+    - seriesQuery: '{__name__=~"^container_.*",container_name!="POD",namespace!="",pod_name!=""}'
+      seriesFilters:
+      - isNot: ^container_.*_total$
+      resources:
+        overrides:
+          namespace:
+            resource: namespace
+          pod_name:
+            resource: pod
+      name:
+        matches: ^container_(.*)$
+        as: ""
+      metricsQuery: sum(<<.Series>>{<<.LabelMatchers>>,container_name!="POD"}) by (<<.GroupBy>>)
+    - seriesQuery: '{namespace!="",__name__!~"^container_.*"}'
+      seriesFilters:
+      - isNot: .*_total$
+      resources:
+        template: <<.Resource>>
+      name:
+        matches: ""
+        as: ""
+      metricsQuery: sum(<<.Series>>{<<.LabelMatchers>>}) by (<<.GroupBy>>)
+    - seriesQuery: '{namespace!="",__name__!~"^container_.*"}'
+      seriesFilters:
+      - isNot: .*_seconds_total
+      resources:
+        template: <<.Resource>>
+      name:
+        matches: ^(.*)_total$
+        as: ""
+      metricsQuery: sum(rate(<<.Series>>{<<.LabelMatchers>>}[5m])) by (<<.GroupBy>>)
+    - seriesQuery: '{namespace!="",__name__!~"^container_.*"}'
+      seriesFilters: []
+      resources:
+        template: <<.Resource>>
+      name:
+        matches: ^(.*)_seconds_total$
+        as: ""
+      metricsQuery: sum(rate(<<.Series>>{<<.LabelMatchers>>}[5m])) by (<<.GroupBy>>)