Support filling postgres from sqlite and dumping postgres to sqlite

[stevejalim]

Description

As part of integrating Wagtail into Bedrock, we'll have a RDBMs (Postgres) connected to an 'editing node' running Bedrock, and will export a sqlite DB with that same data, which the web pods will use (They currently use sqlite now, so this is just changing how we update/maintain the main sqlite DB that gets copied down to each web pod)

Of course, we'll also need to set up the latest version of Bedrock data in that postres DB before we can dump data from it

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Success Criteria

• A script will fill an empty postgres DB with an equivalent of the data from the latest cut of the sqlite DB
• A script exists that will genrate a new, sqlite DB from a postgres DB that is connected to (local) Bedrock
• When Bedrock is configured to use that generated sqlite DB, all data is usable, just as it is now.