Add databricks workflow examples

[mooneyc6]

Includes two Databricks examples

• Simple hello-world example for triggering model runs from Nextmv on Databricks and tracking results
• ML to Opt example from the Gurobi Avocado price optimization notebook (ML on Databricks and Opt on Nextmv)

[mooneyc6]

@nmisek could use some help with the linter and tests tomorrow