Remove last remaining parts of glint v1 #219

Job	Run time
Slow tests: typescript with npm	1m 32s
Slow tests: defaults with npm	1m 15s
Lint	20s
Slow tests: try-scenarios	2m 10s
Slow tests: typescript with pnpm	53s
Slow tests: defaults with pnpm	50s
Tests (monorepo with npm)	15s
Tests (test-app-location)	18s
Tests (declarations-configuration)	34s
Tests (addon-location)	14s
Tests (monorepo with pnpm)	19s
Tests (rollup-build)	19s
Tests (addon-only)	12s
	9m 11s

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