(SUP-2384) Resource ordering issue with Rsan::Exporter/Pe_postgresql_psql

[MartyEwings]

Describe the Bug

On primary server or replica first commission with RSAN its possible yo will bump into the following issue

Error: /Stage[main]/Rsan::Exporter/Pe_postgresql_psql[GRANT SELECT ON ALL TABLES IN SCHEMA "public" TO rsan on pe-activity]: Could not evaluate: Error evaluating 'unless' clause: 'Error: Could not execute posix command: Invalid group: postgres
'
Error: /Stage[main]/Rsan::Exporter/Pe_postgresql_psql[GRANT SELECT ON ALL TABLES IN SCHEMA "public" TO rsan on pe-classifier]: Could not evaluate: Error evaluating 'unless' clause: 'Error: Could not execute posix command: Invalid group: postgres
'
Error: /Stage[main]/Rsan::Exporter/Pe_postgresql_psql[GRANT SELECT ON ALL TABLES IN SCHEMA "public" TO rsan on pe-inventory]: Could not evaluate: Error evaluating 'unless' clause: 'Error: Could not execute posix command: Invalid group: postgres
'
Error: /Stage[main]/Rsan::Exporter/Pe_postgresql_psql[GRANT SELECT ON ALL TABLES IN SCHEMA "public" TO rsan on pe-puppetdb]: Could not evaluate: Error evaluating 'unless' clause: 'Error: Could not execute posix command: Invalid group: postgres
'
Error: /Stage[main]/Rsan::Exporter/Pe_postgresql_psql[GRANT SELECT ON ALL TABLES IN SCHEMA "public" TO rsan on pe-rbac]: Could not evaluate: Error evaluating 'unless' clause: 'Error: Could not execute posix command: Invalid group: postgres
'
Error: /Stage[main]/Rsan::Exporter/Pe_postgresql_psql[GRANT SELECT ON ALL TABLES IN SCHEMA "public" TO rsan on pe-orchestrator]: Could not evaluate: Error evaluating 'unless' clause: 'Error: Could not execute posix command: Invalid group: postgres
'

Environment

2019.8.6 and 2021.1