Add secure property to environment in Configuration

This is populated by Play's configuration so it can switch on the
currently running application. Each sub-project can specify if it
should be run securely.

The value of this secure property is used to choose the correct URLs
for URL path values elsewhere in the config.
Add thegulocal to CORS origin property
Merge remote-tracking branch 'origin/master' into secure-configuration

Conflicts:
	common/app/common/configuration.scala
Merge pull request #1822 from guardian/secure-configuration

Secure configuration