[AUR-411] Adopt to Example2 project (#28)

Add the chatbot from Example2. Create the UI for chat.

knowledgehub/contribs/promptui/ui/__init__.py

@@ -0,0 +1,45 @@
+from typing import Union
+
+import gradio as gr
+import yaml
+from theflow.utils.modules import import_dotted_string
+
+from ..themes import John
+from .chat import build_chat_ui
+from .pipeline import build_pipeline_ui
+
+
+def build_from_dict(config: Union[str, dict]):
+    """Build a full UI from YAML config file"""
+
+    if isinstance(config, str):
+        with open(config) as f:
+            config_dict: dict = yaml.safe_load(f)
+    elif isinstance(config, dict):
+        config_dict = config
+    else:
+        raise ValueError(
+            f"config must be either a yaml path or a dict, got {type(config)}"
+        )
+
+    demos = []
+    for key, value in config_dict.items():
+        pipeline_def = import_dotted_string(key, safe=False)
+        if value["ui-type"] == "chat":
+            demos.append(build_chat_ui(value, pipeline_def))
+        else:
+            demos.append(build_pipeline_ui(value, pipeline_def))
+    if len(demos) == 1:
+        demo = demos[0]
+    else:
+        demo = gr.TabbedInterface(
+            demos,
+            tab_names=list(config_dict.keys()),
+            title="PromptUI from kotaemon",
+            analytics_enabled=False,
+            theme=John(),
+        )
+
+    demo.queue()
+
+    return demo