Consolidate utility views into a single view

Combine ps_to_bb_course_code and half_vs_full_courses views into a
single view, keyed to the PeopleSoft course code.
Add placeholders for consolidate D2L & Ares views

Declare three new views that will consolidate the various views in use
for Desire2Learn and Ares data exports. The new views will reduce
duplication and overhead.