No Google Analytics / analytics integration support

[MelbourneDeveloper]

Problem

The dart_node site includes Google Analytics in the base template. The plugin provides no way to inject analytics scripts.

Current workaround

The {% block head %} in base.njk can be used to add analytics, but:

1. This requires overriding the entire base template
2. There's no documented approach for analytics integration

Suggestion

Add a config option like:

techdocPlugin({
  analytics: {
    google: 'G-XXXXXXXXXX'
  }
})

Or at minimum, document how to use {% block head %} for analytics injection.