BREAKING: get rid of the LegacyWaffle-based CourseWaffleFlag.
Both CourseWaffleFlag and FutureCourseWaffleFlag now use the modern
WaffleFlag as parent class. FutureCourseWaffleFlag left to support ORA
transition to modern waffle.
Switch to the ORA version which supporting new Waffles.
This is a first stage for removing the LegacyWaffle* classes.
LegacyWaffleFlag usage replaced with WaffleFlag;
LegacyWaffleSwitche usage replaced with WaffleSwitch;
New CourseWaffleFlag added to the temporary module __future__ as FutureCourseWaffleFlag;
Updated all the imports to use CourseWaffleFlag from the __future__ module;
BREAKING CHANGE: A number of toggle related constants (e.g. ENABLE_ACCESSIBILITY_POLICY_PAGE)
changed types. They were strings, and are now toggle instances (e.g. WaffleSwitch). Although the entire
refactor should be self-contained in edx-platform, if any plugins or dependencies were directly
using these constants, they will break. If this is the case, try to find a better publicized way of
exposing those toggles.
