toastergui: consistent add / remove layer notifications

toastergui: consistent add / remove layer notifications

In my struggle to ensure consistency in the format and content
of the notifications we show when you add and remove layers to
a project, I've:

* added the project name to the notifications
in the layer details page

* removed the 'Go to project configuration' link
from the notifications in the layer details page

This changes align the notifications we show in the layer
details page with the ones we show in the 'all' pages.

Signed-off-by: Belen Barros Pena <belen.barros.pena@intel.com>