update MAM2EBRAINS of PR record from inm-6/multi-area-model/master

created VERSION_LOG.md to record all changes made in every release version

created VERSION_LOG.md for recording the changes made in every release

in .gitignore files added multiarea_model/data_multiarea/.ipynb_checkpoints/* to ignore all checkpoints files

updated the file SLN_logdensities.R by changing the separator from '" to '/"

Update SLN_logdensities.R