create a first draft of the global stats pages (/about-*)

ippisite/ippidb/templates/about-general.html

ippisite/ippidb/templates/about-pharmacology.html

ippisite/ippidb/templates/about-physicochemistry.html

ippisite/ippidb/templates/about.html

ippisite/ippidb/templates/base.html

ippisite/ippidb/templates/compound_card.html

ippisite/ippidb/templates/general.html

ippisite/ippidb/templates/physicochemistry.html

ippisite/ippidb/urls.py

ippisite/ippidb/views/__init__.py

ippisite/ippidb/views/compound_query.py