Allow to use a local settings file

Signed-off-by: Emmy D'Anello <emmy.danello@animath.fr>

tfjm/settings.py

@@ -284,3 +284,8 @@ if TFJM_STAGE == "prod":  # pragma: no cover
     from .settings_prod import *  # noqa: F401,F403
 else:
     from .settings_dev import *  # noqa: F401,F403
+
+try:
+    from .settings_local import *
+except ImportError:
+    pass