Release v1.9.8

• [FIXED] the backend.check_kirchoff function was not correct when some elements were disconnected
  (the wrong columns of the p_bus and q_bus was set in case of disconnected elements)
• [FIXED] PandapowerBackend, when no slack was present
• [FIXED] the "BaseBackendTest" class did not correctly detect divergence in most cases (which lead
  to weird bugs in failing tests)
• [FIXED] an issue with imageio having deprecated the fps kwargs (see #569)
• [FIXED] adding the "loads_charac.csv" in the package data
• [FIXED] a bug when using grid2op, not "utils.py" script could be used (see
  #577). This was caused by the modification of
  sys.path when importing the grid2op test suite.
• [ADDED] A type of environment that does not perform the "emulation of the protections"
  for some part of the grid (MaskedEnvironment) see #571
• [ADDED] a "gym like" API for reset allowing to set the seed and the time serie id directly when calling
  env.reset(seed=.., options={"time serie id": ...})
• [IMPROVED] the CI speed: by not testing every possible numpy version but only most ancient and most recent
• [IMPROVED] Runner now test grid2op version 1.9.6 and 1.9.7
• [IMPROVED] refacto gridobj_cls._clear_class_attribute and gridobj_cls._clear_grid_dependant_class_attributes
• [IMPROVED] the bahviour of the generic class MakeBackend used for the test suite.
• [IMPROVED] re introducing python 12 testing
• [IMPROVED] error messages in the automatic test suite (AAATestBackendAPI)