adding benchmark logic for HKDF

git-svn-id: https://gnunet.org/svn/gnunet@31860 140774ce-b5e7-0310-ab8b-a85725594a96
extending ATS api suggest callback with peer id
adding suggest continuation


git-svn-id: https://gnunet.org/svn/gnunet@31861 140774ce-b5e7-0310-ab8b-a85725594a96