refactor: [DIOS-7056] Separate unit and integration tests

[bcostdolby]

No description provided.

[eck1001]

Not super relevant for testing. But I see that this is a ts project. We should be able to use path mapping to handle relative imports a bit better. check out: https://www.typescriptlang.org/tsconfig/#paths

We just need to double check that our TS version has the feature included.

UPDATE: Sorry, I forgot we are using commonjs require syntax here. Really should upgrade to ESM's and use import/export. It allows tree shaking and slightly better performance. Let me know if anyone knows of any cons but with the native support introduced, I think with node v12, it should be easy to update modules. -- This is definitely a topic outside of this PR. I'll post it elsewhere.