Add `lanyon configure` command
Add `lanyon configure` command

This initializes the cache directory without running a build.

In the content repo, eslint requires that `.lanyon/webpack.config.js`
already exists, which it does not in a fresh clone on CI. Running
`lanyon configure` first would be a performant way to do that setup.

kvz/lanyon,kvz/lanyon,kvz/lanyon,kvz/lanyon