Convert to v2 format addons in `app` blueprint

[SergeAstapov]

Scope of this ticket is to track progress converting addons from default app and addon blueprints to v2 format.

Addons with runtime only functionality, first candidates for conversion:

• [x] ember-welcome-page
• [x] ember-page-title https://github.com/ember-cli/ember-page-title/releases/tag/v8.0.0
• [ ] @ember/test-helpers WIP https://github.com/emberjs/ember-test-helpers/pull/1381
• [ ] @glimmer/component
• [ ] @glimmer/tracking
• [ ] ember-data
• [x] ember-export-application-global (not needed due to https://github.com/ember-cli/ember-cli/pull/9825)
• [ ] ember-load-initializers https://github.com/ember-cli/ember-load-initializers/pull/303
• [x] ember-maybe-import-regenerator (not needed due to https://github.com/ember-cli/ember-cli/pull/9604)
• [ ] ember-resolver WIP https://github.com/ember-cli/ember-resolver/pull/852
• [ ] ember-source (larger lift, already planned during v4 lifecycle)
• [x] qunit-dom released as v2 in v3.0.0
• [ ] [@ember/string] WIP https://github.com/emberjs/ember-string/pull/425

Addons with build-time functionality, conversion may not be straightforward or not needed:

• @ember/optional-features Build-time features validation, has ember-cli commands feature:list, feature:enable, feature:disable
• @embroider/compat (not an addon)
• @embroider/core (not an addon)
• @embroider/webpack (not an addon)
• broccoli-asset-rev (unmaintained, and not part of the Embroider future)
• ember-auto-import
• ember-cli (not an addon)
• ember-cli-app-version
• ember-cli-babel
• ember-cli-dependency-checker
• ember-cli-htmlbars
• ember-cli-inject-live-reload
• ember-cli-sri (archived, and under Embroider, we should see if we can leverage something like https://www.npmjs.com/package/webpack-subresource-integrity)
• ember-cli-terser (not used/needed under Embroider)
• ember-fetch
• ember-qunit - released as v2 in v8.0.0
• ember-template-lint
• loader.js (may be converted if we get rid of dynamism from index.js)

[bertdeblock]

@SergeAstapov You can tick off the ember-export-application-global one. https://github.com/ember-cli/ember-cli/pull/9825#issuecomment-1099241261 is merged 🎉

[bertdeblock]

@SergeAstapov ember-maybe-import-regenerator has already been deleted as well some time ago: https://github.com/ember-cli/ember-cli/pull/9604

[bertdeblock]

FYI, ember-template-lint is not an addon.

[bertdeblock]

Striked through ember-cli-sri, ember-cli and broccoli-asset-rev as well.

[jelhan]

ember-qunit has been converted to v2 addon in recent v8.0.0 release as well.

[NullVoxPopuli]

as has qunit-dom, in v3.0.0

[NullVoxPopuli]

@ember/string here: https://github.com/emberjs/ember-string/pull/425 (not released yet)