move everything to backend folder for migration to dashboard repository

backend/helpers/exceptions.py

@@ -0,0 +1,8 @@
+
+"""Custom exception handler to raise consistent exceptions, as different backend
+raise different exceptions"""
+
+class BackendError(Exception):
+    """The backend error is raised when interacting with
+    the backend fails or gives an unexpected result. The
+    error contains a oneliner description of the problem"""