Add ability to exclude db/bucket tag from influxdb outputs (#6184)

plugins/outputs/influxdb_v2/README.md

@@ -26,6 +26,9 @@ The InfluxDB output plugin writes metrics to the [InfluxDB v2.x] HTTP service.
   ## tag is not set the 'bucket' option is used as the default.
   # bucket_tag = ""
 
+  ## If true, the bucket tag will not be added to the metric.
+  # exclude_bucket_tag = false
+
   ## Timeout for HTTP messages.
   # timeout = "5s"