Add `DATABASE_LOGGING` env variable to control sql logging

[fwextensions]

• In the dev environment, database logging is on by default. Setting DATABASE_DEV_LOGGING to false can clean up the console logs when debugging other things.
• Add flag to example.env.
• Update browserslist database.

[francisli]

What if, instead of a dev-specific env var, we make a more generic DATABASE_LOGGING env var, and use it on both dev and production, with appropriate fallbacks to true/false in the respective environments?

That might be useful for doing quick debugging on production as well...

[fwextensions]

Sounds good. It was only logging on dev, so limited it to that.

[fwextensions]

Updated to apply the DATABASE_LOGGING flag to every environment, with different defaults for each.