Docs, docs, docs

When we first launched the beta, our documentation was limited to our Quickstart Guide. But we have added a lot more over the past few weeks. Notably, we have added integration guides for CI providers like GitHub Actions, CircleCI, Travis CI, and Google Cloud Build so you can quickly try out Depot inside your existing CI provider. If you prefer to try out Depot locally, we also put together a Local Development guide to get you started.