Add article on how to add cookie consent banners

[daveaglick]

This isn't really a Wyam problem, but there have been several requests for built-in GDPR banners. We could add a banner to each theme and then make it a global option to turn on.

[daveaglick]

Another approach would be to do something even more general like inject GDPR banners into the HTML using a module - but I think I prefer adding them to the theme so that they can be styled correctly and as appropriate for each one.

[daveaglick]

I take it back! There's just too many different scenarios and options to cover with a single switch in Wyam, particularly when it comes to what you do if the user denies cookies. Any cookie consent banners should be added by the user to the footer in the layout as needed. https://cookieconsent.insites.com/ has a great library and wizard that makes generating the consent banners super easy.

All that said, a documentation page on how to add consent banners couldn't hurt so I'm going to refactor this issue to a documentation one.