Deprecate `import Ember from 'ember'` #8927

Job	Run time
Type Checking (current version)	41s
Basic Test	2m 17s
Linting	1m 6s
Type Checking (other supported versions) (4.9)	1m 0s
Type Checking (other supported versions) (5.0)	56s
Type Checking (other supported versions) (5.1)	1m 5s
Type Checking (other supported versions) (5.2)	1m 4s
Type Checking (other supported versions) (5.3)	56s
Blueprint Tests	8m 6s
Browserstack Tests (Safari, Edge)	2m 13s
Smoke tests (Full Ember Apps)	1m 36s
Browser Tests (Firefox)	2m 18s
Node.js Tests	1m 3s
All deprecations enabled	1m 36s
All deprecations enabled, with optional features	1m 41s
Deprecations as errors	1m 40s
Deprecations as errors, with optional features	1m 41s
Production build	1m 39s
Production build, with optional features	1m 33s
Extend prototypes	1m 36s
Extend prototypes, with optional features	1m 35s
Prebuilt	1m 50s
Deploy tags to npm	0s
Publish channel to s3	0s
Notify Discord	0s
Publish alpha from default branch	0s
	39m 12s

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