Footer component print styles could be improved

[andysellick]

The layout footer component doesn't have a print stylesheet (although it does rely on the govuk-frontend component scss, so there may be something in there). It currently prints as shown below.

Thoughts:

• does it need both the thick blue line and the thin grey line? Seems like one would be enough, and if it's the blue one, it doesn't need to be quite so thick?
• does it need to take up so much space?
• there are also some pages where the blue line is very close to the content above e.g. https://www.gov.uk/foreign-travel-advice/usa/entry-requirements

Related PR: #3110