added PromptTemplateAdapter

Author: udbhav4

integrations/dspy/src/haystack_integrations/components/generators/dspy/prompt_template_adapter.py

@@ -0,0 +1,31 @@
+class PromptTemplateAdapter:
+    """ Makes DSPy base prompts better with custom model templates, for an enhanced text output. """
+
+    templates = {
+        "mistral": "[INST] {prompt} [/INST]",
+        "llama":   "<s>[INST] {prompt} [/INST]",
+        "chatml":  "<|im_start|>user\n{prompt}<|im_end|>\n<|im_start|>assistant",
+        "default": "{prompt}",
+    }
+    # Templates currently made for only 3 models as samples. This can be extended.
+    # (function written below
+
+
+    def __init__(self, model_family: str = "default"):
+        if model_family not in self.templates:
+            self.template = self.templates["default"]
+        else:
+            self.template = self.templates[model_family]
+        
+        self.model_family = model_family
+
+
+    def wrap(self, prompt: str) -> str:
+        return self.template.format(prompt=prompt)
+
+
+    # Makes addition of models and the templates possible.
+    @classmethod
+    def register_template(cls, name: str, template: str) -> None:
+        """Allow users to add custom model families."""
+        cls.templates[name] = template