Include the UTF8 encoding command for Postgres in Nexus Repository documentation

The UTF8 encoding command for Postgres needs to be included in Nexus Repository documentation.

Issue

The Nexus Repository documentation on Configuring for External PostgreSQL section at: https://help.sonatype.com/repomanager3/installation-and-upgrades/configuring-nexus-repository-pro-for-h2-or-postgresql#ConfiguringNexusRepositoryProforH2orPostgreSQL-ConfiguringforExternalPostgreSQL

does not advise customers to create a Postgres database using UTF8 encoding and this has caused character encoding-related issues.

Improvement
An improvement would be to include the UTF8 encoding commands as the IQ Server Prepare the PostgreSQL Server section does: 
https://help.sonatype.com/iqserver/configuring/external-database-configuration/data-migration-to-postgresql?_ga=2.232166559.1032937219.1665383523-1360092898.1657289893#DataMigrationtoPostgreSQL-PreparethePostgreSQLServer