Update directory of font assets in starter_theme_kit

Problem/Motivation

In web/themes/contrib/civictheme/civictheme_starter_kit/components/variables.base.scss Roboto is referenced as follows:

'#{$ct-assets-directory}fonts/Roboto/Roboto-Regular.ttf'

But should be

'#{$ct-assets-directory}fonts/roboto/Roboto-Regular.ttf'

This in turn causes an error on building new site and using starter_theme:

<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Regular.ttf referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Regular.ttf didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Italic.ttf referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Italic.ttf didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Bold.ttf referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Bold.ttf didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-BoldItalic.ttf referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-BoldItalic.ttf didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Thin.ttf referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Thin.ttf didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Black.ttf referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Black.ttf didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/DancingScript/DancingScript-Regular.ttf referenced in <sub_theme_path>dist/assets/fonts/DancingScript/DancingScript-Regular.ttf didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Regular.woff referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Regular.woff didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Italic.woff referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Italic.woff didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Bold.woff referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Bold.woff didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-BoldItalic.woff referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-BoldItalic.woff didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Thin.woff referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Thin.woff didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Black.woff referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Black.woff didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/DancingScript/DancingScript-Regular.woff referenced in <sub_theme_path>dist/assets/fonts/DancingScript/DancingScript-Regular.woff didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Regular.eot referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Regular.eot didn't resolve at build time, it will remain unchanged to be resolved at runtime<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Italic.eot referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Italic.eot didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Bold.eot referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Bold.eot didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-BoldItalic.eot referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-BoldItalic.eot didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Thin.eot referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Thin.eot didn't resolve at build time, it will remain unchanged to be resolved at runtime
<sub_theme_path>dist/assets/fonts/Roboto/Roboto-Black.eot referenced in <sub_theme_path>dist/assets/fonts/Roboto/Roboto-Black.eot didn't resolve at build time, it will remain unchanged to be resolved at runtime

Proposed resolution

Update references to roboto to `'#{$ct-assets-directory}fonts/roboto/Roboto-Regular.ttf'` in `variables.base.scss

Remaining tasks

User interface changes

API changes

Data model changes