METADATA tables for policy/docker db-migrator should be different than counterpart in policy/drools-pdp seed

I believe I raised this issue in a review and don't want it to get lost.

As API and PAP are the only components being migrated this way at this point in time.   The metadata db tables, etc .. should be maintained with a different name so not to conflict with the drools db-migrator metadata tables, provided that the policy/docker db-migrator has deviated somewhat from the seed code.

The change pretty much is to change:

METADATA_DB=migration

to something else in the script