Document alternative Postgres schema creation using bytea columns

With the implementation of BAPL-1513 / JBPM-9264 customers now have an alternative to use RHPAM on Postgres either with a schema containing oid columns (as in previous versions), or bytea columns. This needs to be documented:

• a new schema is required (Red Hat does not provide a migration tool from the oid based schema to the bytea based one)
• the schema needs to be created using the postgresql-bytea-jbpm-schema.sql script
• RHPAM needs to be run with org.kie.persistence.postgresql.useBytea=true

Potential candidates where this could be added to the documentation:
On Premise installation guide