Feature/databricks insert by period

[matt-winkler]

• changes to dbt_project.yml to add databricks related macro search
• adds example profile for databricks
• databricks macro override to remove the schema when creating the relation (otherwise got an error)
• modified materialization code to get rows affected response specific to how databricks returns it (in data and not in response like the other adapters).
• adds a get_rows_inserted macro to handle variance in response for databricks adapter vs. others

[b-per]

LGTM!

I would just maybe recommend updating the README to mention that it should work across Redshift, Postgres, Snowflake, BigQuery and Databricks ; instead of saying it just works for Redshift

Happy for you to merge.