Add a print format for country pages

This is just the routing and slimmer headers for the print styling.
There currently isn't any view code working yet.
Move common publication_metadata view into /shared directory

This partial is now being called from multiple views outside of those
used by the 'root' controller. Use the rails idiom of keeping shared
partials in the /shared directory.
Printed country travel advice contains all parts

The printer-friendly country travel advice should be a single page
with all of the parts inlined.
Don't show part numbers in printer-friendly country view

Also re-arranged wording of the title.
Simplify with_options usage for travel_advice_country

No need to declare the :as parameter for all of the block, only for
the parts where we need to call this method.
Merge remote branch 'origin/travel-advice-printer-friendly'