Add ThirdPartyLicenses.csv with separate tools
Created by: felixfbecker
Different approach to https://github.com/sourcegraph/sourcegraph/pull/9554 with separate tools for JS and Go. Includes the deps for JS.
@tsenart you can push to this branch to add a command that outputs CSV for Go.
I left out the CI up-to-date check for now because it would break Renovate PRs completely, but it will check in CI for any GPL licenses being present (using the latest yarn.lock).
@sourcegraph/code-intel I made sure devDependencies don't actually end up in the Docker images since we don't check their licenses, some help in a quick smoke test would be appreciated