[AUR-338, AUR-406, AUR-407] Export pipeline to config for PromptUI. Construct PromptUI dynamically based on config. (#16)

From pipeline > config > UI. Provide example project for promptui

- Pipeline to config: `kotaemon.contribs.promptui.config.export_pipeline_to_config`. The config follows schema specified in this document: https://cinnamon-ai.atlassian.net/wiki/spaces/ATM/pages/2748711193/Technical+Detail. Note: this implementation exclude the logs, which will be handled in AUR-408.
- Config to UI: `kotaemon.contribs.promptui.build_from_yaml`
- Example project is located at `examples/promptui/`

knowledgehub/llms/completions/base.py

@@ -27,7 +27,7 @@ class LangchainLLM(LLM):
                 self._kwargs[param] = params.pop(param)
         super().__init__(**params)
 
-    @Param.decorate()
+    @Param.decorate(no_cache=True)
     def agent(self):
         return self._lc_class(**self._kwargs)