confd: add new factory user admin:admin

This patch adds a new user "admin" with the password "admin". The
password is hashed with sha512 ($6) as a hint to new users attempting
to change the password (avoid the weakest algorithms).

Signed-off-by: Richard Alpe <richard@bit42.se>

board/netconf/rootfs/etc/auto-factory.d/10-authentication.json

@@ -0,0 +1,12 @@
+{
+  "ietf-system:system": {
+    "authentication": {
+      "user": [
+        {
+          "name": "admin",
+          "password": "$6$bKPp6xu45L1cmp70$fcwDhGZct4q8LxwPASf9iVHyWqnklcdjeYi/SupLo1K9nb.aAQUz48.3qTcW38XL6gQzfHyGoyeDG2orjPUwm1"
+        }
+      ]
+    }
+  }
+}