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/utils.ts

@@ -0,0 +1,28 @@
+import { DataGridCoordinates } from "./types"
+
+export function generateCellId(coords: DataGridCoordinates) {
+  return `${coords.row}:${coords.col}`
+}
+
+/**
+ * Check if a cell is equal to a set of coords
+ * @param cell - The cell to compare
+ * @param coords - The coords to compare
+ * @returns Whether the cell is equal to the coords
+ */
+export function isCellMatch(
+  cell: DataGridCoordinates,
+  coords?: DataGridCoordinates | null
+) {
+  if (!coords) {
+    return false
+  }
+
+  return cell.row === coords.row && cell.col === coords.col
+}
+
+const SPECIAL_FOCUS_KEYS = [".", ","]
+
+export function isSpecialFocusKey(event: KeyboardEvent) {
+  return SPECIAL_FOCUS_KEYS.includes(event.key) && event.ctrlKey && event.altKey
+}