Add ESLint to Gazebo

[rohan-at-sentry]

• Pick Gazebo
• get some sort of static analysis into gazebo if it isn't there (ESLint is a good bet and start downloading those artifacts as they're generated in CI
• Alternatively, check out a certain commity in the past that matches a Sentry Release, add ESLint locally, run locally, store output

[rohan-at-sentry]

@nicholas-codecov added JSON outputting to ESLint run step on Gazebo. That step should only show errors like so. Now we need to figure out how to grab it the output

1. We could output to file but how do we grab it?
2. We could simply manually grab logs every week.
3. We could just run locally everytime and grab the file.