update postgresql test server to embedded postgres

[xsalefter]

This is a sub-task from this: #552

Since PostgreSQL update more important (needed to update jooq, also it's old already), we'll cofus with it as the first step:

Step A: Update killbill-commons

1. Change killbill-commons to update testing-postgresql-server with embedded-postgres.
2. Use killbill-commons local SNAPSHOT in killbill-platform and killbill
3. Test them, once everything Ok, send PR

Step B: Update killbill-platform

1. When killbill-commons available in sonatype, update killbill-platfrom from testing-postgresql-server to embedded-postgres.
2. Use killbill-platform local SNAPSHOT in killbill, and test them.
3. Use killbill-platfrom local SNAPSHOT in killbill-stripe/braintree-plugin, update jooq version, and test them.
4. Once everything Ok, send PR

Step C: Update killbill-oss-parent

We have killbill-commons and killbill-platform with up-to-date embedded-postgres migration, so:

1. Update killbill-oss-parent with up-to-date killbill-commons and killbill-platform, build locally.
2. Use killbill-oss-parent local SNAPSHOT in killbill-stripe/braintree-plugin, update jooq version, and test them.
3. Use killbill-oss-parent local SNAPSHOT in killbill, and run test, and manual test with plugins installed, if needed.
4. Once everything Ok, send PR

Last Step

1. Once everything Ok, send PR for killbill with up-to-date killbill-oss-parent
2. Delete killbill-embeddeddb-postgresql in killbill-commons It's still used as test-jar dependency

[xsalefter]

Since this PR merged, then this is considered as complete.