Try to change Astro Python SDK check example DAGs to use GreatExpecatations

[tatiana]

Context We've been having discussions about the Astro Python SDK check strategy. It feels there is an overlap with Great Expectations.

As part of this, we created:

1. https://github.com/astro-projects/astro/issues/298
2. https://github.com/astro-projects/astro/issues/301

The idea with this ticket is, once the ticket https://github.com/astro-projects/astro/issues/301 is completed, to change these (check) example DAGs to use the Great Expectations operator.

Acceptance criteria

• [ ] Pair with someone who has been involved with the development of the GreatExpectations operator (Benji Lampel?)
• [ ] Have a version of the (check) example DAGs using Great Expectations
• [ ] Based on this experience, propose a way to move forward, documenting the findings

[kaxil]

@dimberman To take a look after completing https://github.com/astro-projects/astro/pull/322

[tatiana]

Since this ticket was initially logged, @utkarsharma2 has led a new work stream on data validation. We can create new ones in future as needed. @utkarsharma2 it would be great if you could add links following up on the current validation story state.