**Background:**
This is a follow-up to the PR that adds sphinx docs.
Googleapis.dev hosts client library documentation for several languages as
well as documentation for core packages such as google-api-core. It is owned
and maintained by the Cloud DevRel Core team.
**About this change:**
The `kokoro/docs/publish-python.sh` script builds the docs with sphinx, then
uses the [googleapis/docuploader](https://github.com/googleapis/docuploader)
tool to publish to googleapis.dev. The publish script is triggered manually
with a Kokoro RELEASE type job. Googlers, see go link
protobuf-docs-python-design for additional internal references.
