Setup statisig account

[jamescrosswell]

We should get a lauchdarkly statsig account and test this out with it (+ dogfood our feature flag integration)

Originally posted by @bruno-garcia in #203 (comment)

[bruno-garcia]

The main goal was to be able to flip CaptureBlockingCalls = true; without redeploy. But an env var might do if we don't want to go full on feature flag