feat(admin-sdk,admin-bundler,admin-shared,medusa): Restructure admin packages (#8988)

**What**
- Renames /admin-next -> /admin
- Renames @medusajs/admin-sdk -> @medusajs/admin-bundler
- Creates a new package called @medusajs/admin-sdk that will hold all tooling relevant to creating admin extensions. This is currently `defineRouteConfig` and `defineWidgetConfig`, but will eventually also export methods for adding custom fields, register translation, etc. 
  - cc: @shahednasser we should update the examples in the docs so these functions are imported from `@medusajs/admin-sdk`. People will also need to install the package in their project, as it's no longer a transient dependency.
  - cc: @olivermrbl we might want to publish a changelog when this is merged, as it is a breaking change, and will require people to import the `defineXConfig` from the new package instead of `@medusajs/admin-shared`.
- Updates CODEOWNERS so /admin packages does not require a review from the UI team.

packages/admin/dashboard/src/lib/schemas.ts

@@ -0,0 +1,36 @@
+import i18n from "i18next"
+import { z } from "zod"
+
+export const AddressSchema = z.object({
+  first_name: z.string().min(1),
+  last_name: z.string().min(1),
+  company: z.string().optional(),
+  address_1: z.string().min(1),
+  address_2: z.string().optional(),
+  city: z.string().min(1),
+  postal_code: z.string().min(1),
+  province: z.string().optional(),
+  country_code: z.string().min(1),
+  phone: z.string().optional(),
+})
+
+export const EmailSchema = z.object({
+  email: z.string().email(),
+})
+
+export const TransferOwnershipSchema = z
+  .object({
+    current_owner_id: z.string().min(1),
+    new_owner_id: z
+      .string()
+      .min(1, i18n.t("transferOwnership.validation.required")),
+  })
+  .superRefine((data, ctx) => {
+    if (data.current_owner_id === data.new_owner_id) {
+      return ctx.addIssue({
+        code: z.ZodIssueCode.custom,
+        path: ["new_owner_id"],
+        message: i18n.t("transferOwnership.validation.mustBeDifferent"),
+      })
+    }
+  })