chore: Fix enterprise frontend build

Created by: efritz

Context: https://sourcegraph.slack.com/archives/CMBA8F926/p1602684842044900

https://buildkite.com/sourcegraph/sourcegraph/builds/76477 is failing because I started using the codeintel database package which imports sqlite utilities from the frontend, which was not being built with cgo enabled.

This enables the sqlite wrapper in the enterprise frontend container and fixes the build script. This is temporary, as we'll be removing all sqlite interaction in the precise code intel flow in the next milestone, so we can revert this once that's done.