Add copyright placeholder to template

* template.rst: We're releasing the documents under a copyright
license so we should declare copyright information within them. In
fact, we're releasing them under a license which requires
attribution, so derivative authors and distributors need to know to
whom they should attribute the originals.

Change-Id: Id0b77da6a65584f9e0f3187a31ca53c9eb087608
Merge "Add copyright placeholder to template"