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/format-provider.ts

@@ -0,0 +1,18 @@
+/**
+ * Providers only have an ID to identify them. This function formats the ID
+ * into a human-readable string.
+ *
+ * Format example: pp_stripe-blik_dkk
+ *
+ * @param id - The ID of the provider
+ * @returns A formatted string
+ */
+export const formatProvider = (id: string) => {
+  const [_, name, type] = id.split("_")
+  return (
+    name
+      .split("-")
+      .map((s) => s.charAt(0).toUpperCase() + s.slice(1))
+      .join(" ") + (type ? ` (${type.toUpperCase()})` : "")
+  )
+}