+ native classes
+ tracked properties
- Ember.Object
- Ember.Evented
- observers
- mixins
- computed/discourseComputed
Also removes unused wizard infrastructure for warnings. It appears
that once upon on time, either the server can generate warnings,
or some client code can generate them, which requires an extra
confirmation from the user before they can continue to the next step.
This code is not tested and appears unused and defunct. Nothing
generates such warning and the server does not serialize them.
Extracted from https://github.com/discourse/discourse/pull/23678
