postgresql instanceID implementation

Author: sv-splunk

cmd/otelcontribcol/builder-config.yaml

@@ -278,3 +278,4 @@ providers:
 # file before passing it to OCB, to ensure that local versions are used for all
 # Contrib modules.
 replaces:
+  - github.com/open-telemetry/opentelemetry-collector-contrib/receiver/postgresqlreceiver => ../../receiver/postgresqlreceiver

receiver/postgresqlreceiver/documentation.md

@@ -456,3 +456,4 @@ top query
 | postgresql.index.name | The name of the index on a table. | Any Str | true |
 | postgresql.schema.name | The schema name. | Any Str | true |
 | postgresql.table.name | The table name. | Any Str | true |
+| service.instance.id | A unique identifier of the PostgreSQL DB instance in the format host:port. (defaults to 'unknown:5432', in case of error in generating this value) | Any Str | true |