Generate and publish documentation on CI

[1ec5]

We should adapt the work @chezzdev did in mapbox/mapbox-navigation-ios#3439 mapbox/mapbox-navigation-ios#3469 to run the jazzy documentation generation script on CI for every PR and push it to publisher-production for release tags. This will completely automate two of the steps of the release process. It would also obviate #650, since no one would need to run publish-documentation.sh manually anymore.

/cc @mapbox/navigation-ios @mapbox/docs