Implement Flyway DB schema migration for Postgresql

The goal of this task is to provide users with a way to migrate the SQL databases when there's a change with the Kogito upgrade.
Users should have the option to migrate the DB at start-up or manually using Flyway CLI.

Flyway has a property `quarkus.flyway.migrate-at-start`, which can be used by users to allow migration on start-up. 
There should be documentation on how to use flyway to migrate the DB manually to have more control. 
There could be a case where users don't want to use flyway, in that case documentation should be provided for executing SQL scripts to create schema manually.