removing logs-lib reference

Author: gaantunes

postgres_mixin/config.libsonnet

@@ -1,8 +1,5 @@
 {
   _config+:: {
-    postgresExporterSelector: if self.enableMultiCluster then self.jobSelector + ', ' + self.instance + '=~\"$instance\",cluster=~\"$cluster\"' else  self.jobSelector + ', ' + self.instance + '=~\"$instance\"',
-    enableMultiCluster: true,
-    instanceLabel: 'instance', //replace to 'pod', in case you are monitoring it on k8s and using pod name as instance selector
-    jobSelector: 'job=~\"$job\"',
+    postgresExporterSelector: '',
   },
 }

postgres_mixin/dashboards/dashboards.libsonnet

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

postgres_mixin/dashboards/postgres-overview.json

@@ -95,7 +95,7 @@
             "uid": "$datasource"
           },
           "dsType": "prometheus",
-          "expr": "sum(irate(pg_stat_database_xact_commit{datname=~\"$db\",job=~\"$job\",instance=~\"$instance\"}[$__rate_interval])) + sum(irate(pg_stat_database_xact_rollback{datname=~\"$db\",job=~\"$job\",instance=~\"$instance\"}[$__rate_interval]))",
+          "expr": "sum(irate(pg_stat_database_xact_commit{datname=~\"$db\",%(postgresExporterSelector)s}[$__rate_interval])) + sum(irate(pg_stat_database_xact_rollback{datname=~\"$db\",%(postgresExporterSelector)s}[$__rate_interval]))",
           "format": "time_series",
           "groupBy": [
             {