feat(auth): add auth middleware

- refactored chat routes to use request.user instead of doing authentication in every route

backend/apps/web/middlewares/auth.py

@@ -0,0 +1,27 @@
+from apps.web.models.users import Users
+from fastapi import Request, status
+from starlette.authentication import (
+    AuthCredentials, AuthenticationBackend, AuthenticationError, 
+)
+from starlette.requests import HTTPConnection
+from utils.utils import verify_token
+from starlette.responses import JSONResponse
+from constants import ERROR_MESSAGES
+
+class BearerTokenAuthBackend(AuthenticationBackend):
+
+    async def authenticate(self, conn: HTTPConnection):
+        if "Authorization" not in conn.headers:
+            return
+        data = verify_token(conn)
+        if data != None and 'email' in data:
+            user = Users.get_user_by_email(data['email'])
+            if user is None:
+                raise AuthenticationError('Invalid credentials') 
+            return AuthCredentials([user.role]), user
+        else:
+            raise AuthenticationError('Invalid credentials') 
+
+def on_auth_error(request: Request, exc: Exception):
+    print('Authentication failed: ', exc)
+    return JSONResponse({"detail": ERROR_MESSAGES.INVALID_TOKEN}, status_code=status.HTTP_401_UNAUTHORIZED)