Init dotations handler

server/handlers/dotations.py

+class Dotations(object):
+
+    def home(**params: dict) -> tuple:
+        request_body = params["body"]
+
+        # vérifier le format
+        if "dotations" not in request_body:
+            return {"Error": "Missing 'dotations' field in request body."}, 400
+
+        # calculer
+
+        # constuire la réponse
+        return {"hello": "coucou"}, 200