Remove barrel file imports from internal code for better tree-shaking

Replace all internal barrel imports (from `@ember/-internals/glimmer`,
`@ember/-internals/environment`, etc.) with direct imports from the
specific source files that define what is needed. Also replace all
`export *` patterns in `@ember` packages with explicit named exports.

- Update ~40 source files to import from specific lib paths instead of
  barrel `index.ts` files
- Replace `export *` with named exports in `@ember/-internals/environment`,
  `@ember/engine/parent`, `@ember/template-compiler/*`, `ember-template-compiler`,
  and `ember-testing`
- Replace `import * as environment` with named `{ hasDOM }` import in
  `@ember/application/instance`
- Add deep import path entries to `@ember/-internals/package.json` exports map
- Add `@glimmer/opcode-compiler` dependency to `ember-template-compiler`

Test files are intentionally left unchanged as they may use barrel imports.

Revert manual changes, so we can test lint

Lint rule

Lint rule

Update sub-path exports

Lint rule

Lint rule

eslint

lint:fix

Lockfile

Fix

fix

Author: NullVoxPopuli

eslint-rules/index.js

@@ -0,0 +1,9 @@
+/* eslint-disable no-undef */
+
+'use strict';
+
+module.exports = {
+  rules: {
+    'no-barrel-imports': require('./no-barrel-imports'),
+  },
+};