Update config file

The following deprecation message is displayed on my machine:

"The 'pygments' configuration option has been renamed to 'highlighter'.
Please update your config file accordingly.
The allowed values are 'rouge', 'pygments' or null.
Factor out codepen sample to includes file
Move codepen samples from Front Matter to content

This allows us to place our own content between codepen samples
Merge pull request #1 from matthewdunsdon/enhancement/allow-post-to-position-codepens

Allow 'fundamentals' sample page to create its own codepens