Tidy up the layout.html and template.html files

[chrimesdev]

There is a template.html file which contains all the HTML structure and metadata and also a layout.html which is imports all the Nunjucks macros. However, there is some overlap between the 2, such as the footer and page title being set in both.

We found that setting the footer in the layout.html file wouldn't update as it was overridden by the template.html file.

They could potentially be combined into 1 single file and make it clearer how to update common elements that change such as the Header, Page titles or Footer. As they could be set in multiple places such as page, template or layout and could get a bit messy and confusing.