Mixin Lint fixes (prometheus-community#14)

* lint fixes

* Add .lint exclusion file - for mixtool

* Update .lint exclusion file - for mixtool

Author: gaantunes

postgres_mixin/.lint

@@ -0,0 +1,15 @@
+---
+exclusions:
+  panel-units-rule:
+    reason: Ignoring so far, need to address this in future
+  panel-title-description-rule:
+    reason: Ignoring so far, need to address this in future
+  panel-datasource-rule:
+    reason: "Loki datasource variable is being named as loki_datasource now while linter expects 'datasource'"
+  template-datasource-rule:
+    reason: "Based on new convention we are using variable names prometheus_datasource and loki_datasource where as linter expects 'datasource'"
+  alert-name-camelcase:
+    reason: QPS is a common acronym (Queries Per Second) and should be allowed
+    entries:
+      - alert: PostgreSQLQPS
+    

postgres_mixin/dashboards/postgres-overview.libsonnet

@@ -1338,7 +1338,7 @@
               "query": "label_values(pg_up, job)",
               "refId": "StandardVariableQuery"
             },
-            "refresh": 1,
+            "refresh": 2,
             "regex": "",
             "skipUrlSync": false,
             "sort": 0,
@@ -1372,7 +1372,7 @@
               "query": "label_values(pg_up{job=~\"$job\"},instance)",
               "refId": "StandardVariableQuery"
             },
-            "refresh": 1,
+            "refresh": 2,
             "regex": "",
             "skipUrlSync": false,
             "sort": 0,
@@ -1397,7 +1397,7 @@
               "query": "label_values(pg_stat_database_tup_fetched{%(postgresExporterSelector)s,datname!~\"template.*|postgres\"},datname)" % $._config,
               "refId": "StandardVariableQuery"
             },
-            "refresh": 1,
+            "refresh": 2,
             "regex": "",
             "skipUrlSync": false,
             "sort": 0,