no issue
- upgrade `ember-ajax` to 3.0.0
- `ember-ajax` [now passes the payload through directly](https://github.com/ember-cli/ember-ajax/releases/tag/v3.0.0) rather than trying to normalize it so all our error handling needed to be updated
no issue
- the upcoming Module Unification re-organisation in Ember will no longer support nested components
- this PR pre-emptively moves our usage of nested components into a flat file structure