Add GPG signing of artifacts and POM
Add GPG signing of artifacts and POM

The plugin is added as per guidance mentioned in http://goo.gl/AljV. Use
the settings.xml to specify a property gpg.passphrase against which mention
the password of the key to avoid being prompt for password everytime.

Signed-off-by: Imran M Yousuf <bb5621ada9f40b1f5c463d8e9c51c12e465afec7@smartitengineering.com>

hamnis/http-esi-testbed