Get rid of pytriqs/dmft

This module was deprecated, now we remove it.

  deleted:    pytriqs/dmft/CMakeLists.txt
  deleted:    pytriqs/dmft/__init__.py
  deleted:    pytriqs/dmft/loop_generic.py
  modified:   test/pytriqs/solvers/ctqmc_hyb/cdmft_4_sites.py
  modified:   test/pytriqs/solvers/ctqmc_hyb/single_site_bethe.py
  modified:   test/pytriqs/solvers/ctqmc_hyb/time_acc.py