* Add "pattern" and "component" guidance

* Swap a selection of "pattern" for "component"

* Missed a couple files to commit

* Somehow vf-colors.map.scss was deleted

* Referecne `components/vf-core-components`

This doesn't affect vf-core particuarly, but will affect vf-child-template

* Fix a build error/warning

Not sure when this started happening; was erroring but continuing:

> ⚑ Exported 351 of 910 items
> ✘ Failed to export url /components/detail/vf-button--sizes - (/Users/khawkins/Documents/GitHub/vf-core/tools/vf-frctl-theme/views/pages/components/detail.njk)
>   Template render error: (/Users/khawkins/Documents/GitHub/vf-core/tools/vf-frctl-theme/views/partials/pen/preview.njk)
>   Error: Unable to call `entity["variants"]`, which is undefined or falsey

* updates masthead to be nearer what we need

* updates mark for generic masthead

* adds custom properties to design tokens task

* adds css custom properties files

* alters the HTML to use 'default' custom properties

* adds css custom properties

* whitespace

* adds css custom properties

* updates CSS fallbacks for older browsers

* Update npm-shrinkwrap.json

* Documentation: Add comments on properties and token file location

This is both related to the active PR and a general improvement to "don't edit this file, go edit the design tokens instead"

* Chore: Rund design token task on build

Should help fight entropy with design tokens possibly getting out of sync from Sass

* Clean up a file generation mess

* Add further comments, template refinements

* Fix indentation linting

* changes the wording so it's simpler, fixes some whitespace annoyances

* updated gulp tokens results

* removes IDs that came from the WP list

Doc cleanup

More work to be done here, but beyond making things barely functional, it's probably out of scope for this issue

For https://github.com/visual-framework/vf-core/issues/127

Refactor/nunjucks ification

Feature/nunjucks extensions

This will also help with our documentation efforts:
```
{% set context = '@vf-heading' | patternContexts %}
```

So we don't have to npm install and gulp for ci to get 1 css file.

Depending if we stick with this or use 11ty as a pattern library, we'll need revisist.

Earning all the commit points.

Why? Full customisation, use of "real" VF patterns, .njk file extensions.

Possible 11ty integration too...

This reverts commit a784b25a, reversing
changes made to 8327c8c4.