chore(data-warehouse): Added a timeout for postgres connections

[Gilbert09]

Problem

• If a users postgres doesn't allow our IP addresses, then the SQL connection to check for schemas just hangs until after the the 60sec request timeout, returning a 5xx error to the user with a very unhelpful error message

Changes

• Reduce the connection timeout to 5secs
• Add a friendly error message for when the timeout occurs

Does this work well for both Cloud and self-hosted?

• Yes

How did you test this code?

• Via browser clicky clicks