nac3embedded: add device_db for artiq_run of the compiler output

nac3embedded/device_db.py

@@ -0,0 +1,13 @@
+# python demo.py
+# artiq_run module.elf
+
+core_addr = "192.168.1.50"
+
+device_db = {
+    "core": {
+        "type": "local",
+        "module": "artiq.coredevice.core",
+        "class": "Core",
+        "arguments": {"host": core_addr, "ref_period": 1e-9}
+    }
+}