Publish stories with fastpages

[samvanstroud]

Summary

We need a way to easily publish good-looking stories, fastpages looks like a good option. Here is a test https://samvanstroud.github.io/fastpages-test/2020/10/14/story1.html

What needs to be done?

• [x] Confirm that we are all happy to publish stories with fastpages.
• [x] Make a new fastpages repo to host strories.
• [x] Add this repository as a submodule.
• [x] Configure GitHub actions in the fastpages repo to automatically copy notebooks from the master branch to the correct folder in the fastpages repo.
• [x] Update the story so that we can take full advantage of the fastpages formatting.

[samvanstroud]

Going to host fastpages in a dedicated repo, as fastpages does not currently allow for modifications to the directory structure.

https://github.com/alan-turing-institute/TuringDataStories-fastpages