Move copyFilePath/Name context actions to editor manager

Synchronizing the context menus on the open documents pane and the
editor tool bar.

Change-Id: I29f614d483a425dec58fc1247b691fd433c4acc0
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
DocumentModel: automatically use id from entry's document if that exists

Avoids some manual assignment and is in line with what we do for the
file path and display name.

Change-Id: I4e98af08b44978493987e63962d26f8595c6990b
Reviewed-by: Eike Ziller <eike.ziller@digia.com>