Move Zephyr app into subdirectory.

app/west.yml

@@ -0,0 +1,13 @@
+manifest:
+  remotes:
+    - name: zephyrproject-rtos
+      url-base: https://github.com/zephyrproject-rtos
+    - name: petejohanson
+      url-base: https://github.com/petejohanson
+  projects:
+    - name: zephyr
+      remote: petejohanson
+      revision: kconfig/external-sheilds-shields-as-list-fix
+      import: true
+  self:
+    path: zmk