[receiver/postgresqlreceiver] Added new postgresql metrics to acheive parity with Telegraf

[chan-tim-sumo]

Description

• Added new postgresql metrics in pg_stat_database to acheive parity with Telegraf

	tupUpdated           int64
	tupReturned          int64
	tupFetched           int64
	tupInserted          int64
	tupDeleted           int64
	blksHit              int64
	blksRead             int64

Link to tracking issue

• https://sumologic.atlassian.net/browse/SUMO-208350

Testing

Screenshots:

• postgres table (locally) with tup_updated as 51
• metric displaying the value 51

Documentation

• https://help.sumologic.com/docs/integrations/databases/postgresql/
• https://github.com/influxdata/telegraf/blob/master/plugins/inputs/postgresql/README.md?plain=1#L134-L139
• https://www.postgresql.org/docs/9.6/monitoring-stats.html#:~:text=Table%2028%2D10.%20pg_stat_database%20View

[dmitryax]

Please take a look at the ci failures

[chan-tim-sumo]

fixed! @dmitryax