✨(invitations) add invitation RSVP links in HTML emails (#10)

Also include many fixes and scalingo deployment

src/backend/calendars/settings.py

@@ -119,6 +119,14 @@ class Base(Configuration):
     )
     APP_NAME = values.Value("Calendrier", environ_name="APP_NAME", environ_prefix=None)
     APP_URL = values.Value("", environ_name="APP_URL", environ_prefix=None)
+    CALENDAR_ITIP_ENABLED = values.BooleanValue(
+        False, environ_name="CALENDAR_ITIP_ENABLED", environ_prefix=None
+    )
+    TRANSLATIONS_JSON_PATH = values.Value(
+        "/data/translations.json",
+        environ_name="TRANSLATIONS_JSON_PATH",
+        environ_prefix=None,
+    )
 
     # Security
     ALLOWED_HOSTS = values.ListValue([])
@@ -857,7 +865,7 @@ class Development(Base):
     DEFAULT_FROM_EMAIL = "calendars@calendars.world"
     CALENDAR_INVITATION_FROM_EMAIL = "calendars@calendars.world"
     APP_NAME = "Calendrier (Dev)"
-    APP_URL = "http://localhost:8920"
+    APP_URL = "http://localhost:8921"
 
     DEBUG_TOOLBAR_CONFIG = {
         "SHOW_TOOLBAR_CALLBACK": lambda request: True,
@@ -945,6 +953,7 @@ class Production(Base):
     SECURE_REDIRECT_EXEMPT = [
         "^__lbheartbeat__",
         "^__heartbeat__",
+        r"^api/v1\.0/caldav-scheduling-callback/",
     ]
 
     # Modern browsers require to have the `secure` attribute on cookies with `Samesite=none`