Split pytest tests into unit and integration tests

[dmoore247]

Is your feature request related to a problem? Please describe.
Current, make test requires a databricks host, token and cluster_id.
We should leverage Mock/MagicMock and most testing techniques more extensively.

Describe the solution you'd like
make test should run pure unit tests.
make integration should run tests that require a databricks cluster

Describe alternatives you've considered
Today we testing that generates a job and runs the top notebooks AND we have make test which for several cases requires a cluster.