Add debug messages for sw.{createcopy,docappend}

This adds a lot of SAL_INFO messages to SwDoc::CreateCopy and
SwDoc::Append.

Change-Id: Ie924e20698bec84482fcc5496175a9e29245729e
Reviewed-on: https://gerrit.libreoffice.org/10969
Reviewed-by: Björn Michaelsen <bjoern.michaelsen@canonical.com>
Tested-by: Björn Michaelsen <bjoern.michaelsen@canonical.com>