Add Countries to Pageskin Sponsorships

Because pageskins are often limited to particular countries.
Add Countries to Pageskin Report
Refactor
Add Deduced Editions to Pageskin Report

Editions are deduced from the country that the line item targets.
Merge branch 'master' into kc-pageskin-edition

Conflicts:
	common/test/common/GuardianConfigurationTest.scala
Add Edition to Pageskin Check

Pageskins are optionally only shown in particular editions
and this is now taken into account
in the decision to build the pageskin ad slot.
Update Configuration Hash

DFP pageskin cache file was updated to v3 in an earlier commit.
Remove Duplicate Env Property

DFP network ID is configured twice leading to confusion.
Link Pageskin Ad Units to Section Fronts
Merge pull request #5018 from guardian/kc-pageskin-edition

Pageskin Ads Are Edition-specific