Unify DB test utils

As we are improving the test suite for our DAO layer, we are beginning to see common functionality that can be consolidate into a single test utilities. For example, [`LineageTestUtils`](https://github.com/MarquezProject/marquez/blob/main/api/src/test/java/marquez/db/LineageTestUtils.java), and `DbTestUtils` (introduced in PR https://github.com/MarquezProject/marquez/pull/1260)