Developer-local docs build

./docs/build.sh

The output can be found in generated/docs.

How the Envoy website and docs are updated

1. The docs are published to docs/envoy/latest on every commit to master. This process is handled by CircleCI with the publish.sh script.

2. The docs are published to docs/envoy in a directory named after every tagged commit in this repo. Thus, on every tagged release there are snapped docs.