* feat(core-flows,types,utils,medusa): Update existing line items when adding the same variant to cart
* chore: split steps into 2 for add-to-cart
* chore: split steps into 2 for add-to-cart
* chore: iterate safely
* chore: parallelize upsert
**What**
- remove medusa-core-utils
- dispatch the utils where they belongs
- update usage
**NOTE**
I have been wondering if the graceful class should go into the utils package or medusa package, I ve put it in the medusa package as it seems to be the best place I can see for now and is tight to the server as well. Also, I wanted to avoid the utils package to depends on http and net dependencies, happy to change that if you feel like it
* chore: Clean up authentication middlewares
* chore: Rename AuthUser to AuthIdentity
* feat: Define link between user, customer, and auth identity
* feat: Use links for auth, update auth context content
* fix: Adjust user create command with new auth setup
* fix: Make auth login more dynamic, review fixes
* fix: Change test assertions for created by
