chore: filled in project structure

Added some example basic files containing a functioning /message
endpoint which logs the received message to INFO.

ref: N25B-144

src/control_backend/core/config.py

@@ -0,0 +1,11 @@
+from pydantic import HttpUrl
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+class Settings(BaseSettings):
+    app_title: str = "PepperPlus"
+    
+    ui_url: HttpUrl = "http://locahost:5173"
+    
+    model_config = SettingsConfigDict(env_file=".env")
+    
+settings = Settings()