feat(ember-simple-auth): remove app re-exports

[BobrImperator]

• Removes app re-exports , meaning that Ember-Simple-Auth will no longer automatically add services/session and session-stores/application files.
  They must be imported by users themselves.

This change is made due to processing problems found here #2888 and shipshapecode/swach#1736.
It's been a problem for a long time and with Ember-Data and Ember itself being more explicit around dependencies, we should make the switch too.

The only thing that ESA will continue to export is the initializer, they aren't usually imported and extended by users so they shouldn't cause problems as long as Ember still supports it.

Migration guide:

Add app/services/session.js or app/services/session.ts

import Service from 'ember-simple-auth/services/session';

export default class SessionService extends Service {}

Add app/session-stores/application.js or app/session-stores/application.ts

import AdaptiveStore from 'ember-simple-auth/session-stores/adaptive';

export default class SessionStore extends AdaptiveStore {}

[github-actions]

Some tests with 'continue-on-error: true' have failed:

• classic-test-app test:one ember-canary

Created by continue-on-error-comment

[github-actions]

Some tests with 'continue-on-error: true' have failed:

• classic-test-app test:one ember-canary

• test-app test:one ember-beta

• test-app test:one ember-canary

• classic-test-app test:one ember-beta

  Created by continue-on-error-comment