Automate npm package publishing

[macterra]

An official release should automatically publish all npm packages (in the /packages folder) with the corresponding version.

We would also like to be able to trigger interim version publishing for testing, which should automatically increment the 3rd number in the version, e.g. 1.4.0 -> 1.4.1, and publish.

Ideally we would also like to include beta versions in the test versions, e.g. 1.4.3 -> 1.5.0-beta.0, and then publish with the beta tag.