feat(azure): Added necessary azure components to app

Using respective credentials for both local development as well as
deployment. When deployed on azure, the app authenticates with the SQL
database via Entra ID (formerly active directory) and accesses other
credentials via key vault as a system managed identity.

app/app.py

@@ -5,6 +5,7 @@ from typing import Any, Dict, Tuple
 import dash_auth
 import pandas as pd
 from app_styles import header_style
+from config import check_credentials
 from dash import (
     Dash,
     Input,
@@ -21,6 +22,14 @@ from dash.exceptions import PreventUpdate
 from data_chat import send_message
 from sql_utils import execute_query, test_db_connection
 
+check_credentials()
+
+# first connection to SQL database to mitigate long startup time
+try:
+    test_db_connection()
+except Exception as e:
+    print(f"Error for first connection to Azure SQL Database: {e}")
+
 external_stylesheets = ["https://codepen.io/chriddyp/pen/bWLwgP.css"]
 
 app = Dash(__name__, external_stylesheets=external_stylesheets)
@@ -357,4 +366,5 @@ def run_sql_query(n_clicks: int, value: str) -> str:
 server = app.server
 
 if __name__ == "__main__":
+    print("Hello!")
     app.run(debug=True)