reverting overview dashboard changes

Author: gaantunes

postgres_mixin/config.libsonnet

@@ -1,5 +1,5 @@
 {
   _config+:: {
-    postgresExporterSelector: 'job=~"$job", instance=~"$instance"',
+    postgresExporterSelector: '',    
   },
 }

postgres_mixin/dashboards/dashboards.libsonnet

@@ -1 +1,5 @@
-(import 'postgres-overview.libsonnet')
+{
+  grafanaDashboards+:: {
+    'postgres-overview.json': (import 'postgres-overview.json'),
+  },
+}