Hugo Commands in the Palette

[michaeltlombardi]

As a platen site maintainer, I want to be able to run Hugo commands without having to learn the syntax and use the command line.

This functionality may be readily provided by the Front Matter extension through its site preview feature and custom actions. Being able to do so reliably for theme users will require the implementation of
estruyf/vscode-front-matter#407, which would allow us to publish one (or more) base configurations that users could inherit and extend for their own sites.

Without that feature, we would need to implement a way to:

1. Ship the latest configuration to users when they use the template repository
2. Write a helper to enable users to add the latest configuration to their site if they had already created their own project (we will probably want to do this anyway for convenience)
3. Write helpers for handling configuration updating/downgrading/etc - possibly scripts, possibly GitHub Actions, probably both.