Process and display accessibility risk and forecast data. Optional Module for ISDC

1. Add "accessibility" to your DASHBOARD_PAGE_MODULES setting like this:

   DASHBOARD_PAGE_MODULES = [
       ...
       'accessibility',
   ]
   
   If necessary add "accessibility" in (check comment for description):
       QUICKOVERVIEW_MODULES,
       MAP_APPS_TO_DB_CUSTOM
   
   For development in virtualenv add ACCESSIBILITY_PROJECT_DIR path to VENV_NAME/bin/activate:
       export PYTHONPATH=${PYTHONPATH}:\
       ${HOME}/ACCESSIBILITY_PROJECT_DIR
   

2. To create the accessibility tables:

   python manage.py makemigrations python manage.py migrate accessibility --database geodb