Feature - CircleCI integration

[jamtur01]

Would love to see this work with CircleCI too.

[dcramer]

We need to do two things:

1. Document a basic API to submit build data without native webhook integration
2. Investigate native support for major providers

On the first note, take a look at what Zeus was doing before the Travis hooks:

https://github.com/getsentry/zeus/blob/44558cf1ffc2f7b5714dfb5fc764b7304dddfb59/bin/update-zeus-job

Per that we'd also like to add support to zeus-cli to upsert job/build results in the same way it can submit artifacts today.