Add a wrapper to Causica SCM discovery algorithm

[robertness]

Is your feature request related to a problem? Please describe.
Add a basic wrapper to the DECI algorithm in the causica library.

Describe the solution you'd like
At a first pass, implement with no constraints and no intervention model. Make this an optional dependency.

Describe alternatives you've considered
Causica is a good example of a SCM-based causal discovery algorithm that utilizes deep learning.