Figure out ways to trim services with GitHub write access to repositories

[brittag]

In order for the cloud.gov team to proactively streamline our work and minimize potential surface area for issues with service providers, we should evaluate the services we use listed at "Developer tools that support the cloud.gov system" and figure out where we can cut down that list, particularly any services that have GitHub write access to our repositories.

This task might look like:

• Based on that list, copy out a list of services that we want to assess (perhaps such as Code Climate, Travis CI, Wercker, Codecov, and Circle CI) into a new Google Doc for discussion and note-taking.
• In that doc, write down what might be blocking us from stopping using that service and using something within our system boundary (such as Concourse) or something that has only read access. (Ask for help from other folks on our team to flesh out this list.)
• Work with the relevant folks who are using those services to see if there is any "low-hanging fruit" that we can chop down.
• File a series of tasks to be appropriately prioritized.

Acceptance criteria would probably be:

• [ ] We've assessed our use of external developer tools.
• [ ] We've filed tasks to track trimming or consolidating anything we can trim or consolidate.
• [ ] Those tasks include making sure we update any relevant documentation (including compliance documentation) after we trim something.

[brittag]

We've more or less done this evaluation and taken some action on it - we've trimmed Wercker; we're in the process of trimming Codecov; we have good reasons for Travis CI and Circle CI; Code Climate is important.