Add message to site to explain Javascript is required for best experience

[ad9242]

What is the purpose of the work?

Add a message to the site to explain that Javascript should be enabled in order to get the best experience on the site

Why do we need it?

Following work carried out under #115, the site now displays when Javascript is disabled in the browser. However, some parts do not work correctly as they require Javascript. A message should be added to explain words to that effect - eg "This site requires Javascript. Please enable Javascript in your browser for the best experience"

This might make use of the ic-alert. It should apply to any page, as a user could come in via any url Possibly it could site above the top navigation It should only display when Javascript is disabled

[MI6-255]

Speak to design of where it appears