Initial README for the courseware djangoapp.

lms/djangoapps/courseware/README.rst

+Status: Active Development
+
+Responsibilities
+================
+The courseware djangoapp is responsible for presenting course content to learners.
+
+Glossary
+========
+
+More Documentation
+==================
+`Architectural Decision Records
+<https://github.com/edx/edx-platform/tree/master/lms/djangoapps/courseware/docs/decisions>`_