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/components/data-grid/models/data-grid-bulk-update-command.ts

@@ -0,0 +1,34 @@
+import { Command } from "../../../hooks/use-command-history"
+
+export type DataGridBulkUpdateCommandArgs = {
+  fields: string[]
+  next: any[]
+  prev: any[]
+  setter: (fields: string[], values: any[]) => void
+}
+
+export class DataGridBulkUpdateCommand implements Command {
+  private _fields: string[]
+
+  private _prev: any[]
+  private _next: any[]
+
+  private _setter: (fields: string[], any: string[]) => void
+
+  constructor({ fields, prev, next, setter }: DataGridBulkUpdateCommandArgs) {
+    this._fields = fields
+    this._prev = prev
+    this._next = next
+    this._setter = setter
+  }
+
+  execute(): void {
+    this._setter(this._fields, this._next)
+  }
+  undo(): void {
+    this._setter(this._fields, this._prev)
+  }
+  redo(): void {
+    this.execute()
+  }
+}