Switch from local and @types/ember types to ember-source types (#8717)

* remove @types/ember, add @ember/string

* remove local types, switch to ember stable types

* work around type errors

* Update packages/model/src/-private/errors.ts

* Update packages/store/src/-private/store-service.ts

---------

Co-authored-by: Chris Thoburn <runspired@users.noreply.github.com>

Author: BradBarnich