Add Redshift/PostgreSQL integration

[jbradach]

Is your feature request related to a problem? Please describe.
We have access to a large number of cell phones that aren't in VAN along with communal contactability data through our data warehouse. Because of this, I often pull lists directly via SQL, export them, and then upload them into Spoke.

Describe the solution you'd like
The ability to pull lists from a particular Redshift schema and, ideally, the ability to push data back as a new table.

Describe alternatives you've considered
Since we can already push data from our data warehouse to things like Google Sheets, an alternative could be to integrate with Google Sheets instead.

Additional context

[bchrobot]

Thanks @jbradach -- a SQL integration makes sense to add.

Spoke does have a way to add an instance-wide (not per-organization) SQL warehouse to load from. We have not been actively maintaining that feature but can follow up in an email thread about enabling it for your instance if that would be a helpful stopgap solution.

[jbradach]

That would be great, @bchrobot. Thank you!