Add phi chat prompt template (#1071)

Author: nsarrazin

.env.template

@@ -206,6 +206,7 @@ MODELS=`[
       "modelUrl": "https://huggingface.co/microsoft/Phi-3-mini-4k-instruct",
       "websiteUrl": "https://azure.microsoft.com/en-us/blog/introducing-phi-3-redefining-whats-possible-with-slms/",
       "preprompt": "",
+      "chatPromptTemplate": "{{preprompt}}{{#each messages}}{{#ifUser}}<|user|>\n{{content}}<|end|>\n<|assistant|>\n{{/ifUser}}{{#ifAssistant}}{{content}}<|end|>\n{{/ifAssistant}}{{/each}}",
       "parameters": {
         "stop": ["<|end|>", "<|endoftext|>", "<|assistant|>"],
         "max_new_tokens": 1024,