Deprecate `import Ember from 'ember'` #8928

Job	Run time
Linting	59s
Basic Test	1m 53s
Type Checking (current version)	43s
Type Checking (other supported versions) (4.9)	58s
Type Checking (other supported versions) (5.0)	1m 4s
Type Checking (other supported versions) (5.1)	1m 2s
Type Checking (other supported versions) (5.2)	1m 8s
Type Checking (other supported versions) (5.3)	1m 5s
Blueprint Tests	8m 23s
Browser Tests (Firefox)	2m 21s
Browserstack Tests (Safari, Edge)	2m 48s
Node.js Tests	50s
Smoke tests (Full Ember Apps)	1m 23s
All deprecations enabled	1m 43s
All deprecations enabled, with optional features	1m 42s
Deprecations as errors	1m 34s
Deprecations as errors, with optional features	1m 40s
Production build	1m 38s
Production build, with optional features	1m 32s
Extend prototypes	1m 42s
Extend prototypes, with optional features	1m 47s
Prebuilt	1m 33s
Deploy tags to npm	0s
Notify Discord	0s
Publish alpha from default branch	0s
Publish channel to s3	0s
	39m 28s

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