Upgrade/rollback of database tables

Move table creation into the upgrade/downgrade/install scripts in order to support upgrade/rollback of ONAP releases.

Liquibase may be the required solution.

Policy database DDL can be exported from MariaDB to a file using HeidiSQL.

MariaDB and Postgres(8.2+) work with Liquibase, Cassandra requires an extension.

It can also be used with Hibernate.

We can either integrate Liquibase as part of our application code (Spring boot/Hibernate is the easiest option) or as part of our CI/CD pipeline.

Need to address the table-creation JPA errors currently appearing in the logs