feat(auth): Revamp authentication setup (#7387)

* 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

integration-tests/api/__tests__/admin/publishable-api-key.js

@@ -164,7 +164,7 @@ describe("Publishable API keys", () => {
 
       expect(response.status).toBe(200)
       expect(response.data.publishable_api_key).toMatchObject({
-        created_by: "admin_user",
+        created_by: expect.any(String),
         id: expect.any(String),
         title: "Store api key",
         revoked_by: null,