[Remote Databases] [Step 1] Snowflake connector

[fontanierh]

data model

design doc

Much of the logic should be shared across remote database connectors. We're starting with Snowflake, since it is the one we have.

This task includes fetching secrets from oauth, connecting to a Snowflake DB from connectors, retrieving list of schemas / tables from snowflake, saving the tables in core and implementing the content-nodes API. Can potentially be broken down in smaller task if needed.