[Android] Add Llama2 q4f16_0 (mlc-ai#1041)

llama2 q4f160

Author: spectrometerHBH

android/MLCChat/app/src/main/assets/app-config.json

@@ -1,9 +1,14 @@
 {
   "model_libs": [
+    "Llama-2-7b-chat-hf-q4f16_0",
     "Llama-2-7b-chat-hf-q4f16_1",
     "RedPajama-INCITE-Chat-3B-v1-q4f16_1"
   ],
   "model_list": [
+    {
+      "model_url": "https://huggingface.co/mlc-ai/mlc-chat-Llama-2-7b-chat-hf-q4f16_0/",
+      "local_id": "Llama-2-7b-chat-hf-q4f16_0"
+    },
     {
       "model_url": "https://huggingface.co/mlc-ai/mlc-chat-Llama-2-7b-chat-hf-q4f16_1/",
       "local_id": "Llama-2-7b-chat-hf-q4f16_1"