Revert "Postgres: Switch the datasource plugin from lib/pq to pgx (#103961)" (#106270)

This reverts commit 1e383b0c1e.

pkg/plugins/backendplugin/coreplugin/registry.go

@@ -237,7 +237,7 @@ func NewPlugin(pluginID string, cfg *setting.Cfg, httpClientProvider *httpclient
 	case Tempo:
 		svc = tempo.ProvideService(httpClientProvider)
 	case PostgreSQL:
-		svc = postgres.ProvideService(features)
+		svc = postgres.ProvideService(cfg)
 	case MySQL:
 		svc = mysql.ProvideService()
 	case MSSQL: