Add NonFungibleAdapter (#2924)

This PR introduces a new `NonFungibleAdapter`.

It will be useful for enabling cross-chain Coretime region transfers, as
the existing `NonFungiblesAdapter` is unsuitable for this purpose. This
is due to the fact that there is only one class of items within the
`pallet-broker`, i.e., the Coretime regions.

---------

Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>
Co-authored-by: Dónal Murray <donalm@seadanda.dev>

prdoc/pr_2924.prdoc

@@ -0,0 +1,13 @@
+# Schema: Polkadot SDK PRDoc Schema (prdoc) v1.0.0
+# See doc at https://raw.githubusercontent.com/paritytech/polkadot-sdk/master/prdoc/schema_user.json
+
+title: Add NonFungibleAdapter
+
+doc:
+  - audience: Runtime Dev
+    description: |
+      Introduces a new adapter, `NonFungibleAdapter`, to work with `frame_support::traits::tokens::nonfungible`
+      through XCM.
+
+crates: 
+  - name: staging-xcm-builder