Deprecate `import Ember from 'ember'` #8979

Job	Run time
Linting	1m 5s
Basic Test	2m 32s
Type Checking (current version)	46s
Type Checking (other supported versions) (4.9)	1m 7s
Type Checking (other supported versions) (5.0)	1m 11s
Type Checking (other supported versions) (5.1)	1m 3s
Type Checking (other supported versions) (5.2)	1m 20s
Type Checking (other supported versions) (5.3)	1m 2s
Blueprint Tests	8m 14s
Node.js Tests	53s
Browserstack Tests (Safari, Edge)	3m 13s
All deprecations enabled	1m 42s
Smoke tests (Full Ember Apps) (classic-basics)	1m 11s
All deprecations enabled, with optional features	1m 36s
Smoke tests (Full Ember Apps) (embroider-basics)	1m 18s
Browser Tests (Firefox)	2m 29s
Deprecations as errors	1m 50s
Deprecations as errors, with optional features	1m 38s
Production build	1m 41s
Production build, with optional features	1m 46s
Extend prototypes	1m 38s
Extend prototypes, with optional features	1m 38s
Prebuilt	2m 41s
Publish channel to s3	0s
Notify Discord	0s
Deploy tags to npm	0s
Publish alpha from default branch	0s
	43m 34s

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