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/common/section/index.ts

@@ -0,0 +1 @@
+export * from "./section-row"

packages/admin/dashboard/src/components/common/section/section-row.tsx

@@ -0,0 +1,41 @@
+import { Text, clx } from "@medusajs/ui"
+import { ReactNode } from "react"
+
+export type SectionRowProps = {
+  title: string
+  value?: ReactNode | string | null
+  actions?: ReactNode
+}
+
+export const SectionRow = ({ title, value, actions }: SectionRowProps) => {
+  const isValueString = typeof value === "string" || !value
+
+  return (
+    <div
+      className={clx(
+        `text-ui-fg-subtle grid grid-cols-2 items-center px-6 py-4`,
+        {
+          "grid-cols-[1fr_1fr_28px]": !!actions,
+        }
+      )}
+    >
+      <Text size="small" weight="plus" leading="compact">
+        {title}
+      </Text>
+
+      {isValueString ? (
+        <Text
+          size="small"
+          leading="compact"
+          className="whitespace-pre-line text-pretty"
+        >
+          {value ?? "-"}
+        </Text>
+      ) : (
+        <div className="flex flex-wrap gap-1">{value}</div>
+      )}
+
+      {actions && <div>{actions}</div>}
+    </div>
+  )
+}