Revert "add pgbouncer plugin"

This reverts commit fec9760f72.

plugins/inputs/pgbouncer/README.md

@@ -1,62 +0,0 @@
-# Pgbouncer plugin
-
-This pgbouncer plugin provides metrics for your pgbouncer connection information.
-
-### Configuration:
-
-```toml
-# Description
-[[inputs.pgbouncer]]
-  ## specify address via a url matching:
-  ##   postgres://[pqgotest[:password]]@localhost:port[/dbname]\
-  ##       ?sslmode=[disable|verify-ca|verify-full]
-  ## or a simple string:
-  ##   host=localhost user=pqotest port=... password=... sslmode=... dbname=...
-  ##
-  ## All connection parameters are optional, except for dbname,
-  ## you need to set it always as pgbouncer.
-  address = "host=localhost user=postgres port=6432 sslmode=disable dbname=pgbouncer"
-
-  ## A list of databases to pull metrics about. If not specified, metrics for all
-  ## databases are gathered.
-  # databases = ["app_production", "testing"]
-`
-```
-
-### Measurements & Fields:
-
-Pgbouncer provides two measurement named "pgbouncer_pools" and "pgbouncer_stats", each have the fields as below:
-
-#### pgbouncer_pools
-
-- cl_active
-- cl_waiting
-- maxwait
-- pool_mode
-- sv_active
-- sv_idle
-- sv_login
-- sv_tested
-- sv_used
-
-### pgbouncer_stats
-
-- avg_query
-- avg_recv
-- avg_req
-- avg_sent
-- total_query_time
-- total_received
-- total_requests
-- total_sent
-
-More information about the meaning of these metrics can be found in the [PgBouncer usage](https://pgbouncer.github.io/usage.html)
-
-### Example Output:
-
-```
-$ ./telegraf -config telegraf.conf -input-filter pgbouncer -test
-> pgbouncer_pools,db=pgbouncer,host=localhost,pool_mode=transaction,server=host\=localhost\ user\=elena\ port\=6432\ dbname\=pgbouncer\ sslmode\=disable,user=elena cl_active=1500i,cl_waiting=0i,maxwait=0i,sv_active=0i,sv_idle=5i,sv_login=0i,sv_tested=0i,sv_used=5i 1466594520564518897
-> pgbouncer_stats,db=pgbouncer,host=localhost,server=host\=localhost\ user\=elena\ port\=6432\ dbname\=pgbouncer\ sslmode\=disable avg_query=1157i,avg_recv=36727i,avg_req=131i,avg_sent=23359i,total_query_time=252173878876i,total_received=55956189078i,total_requests=193601888i,total_sent=36703848280i 1466594520564825345
-```
-