fix data model field type

column "value" may also be boolean (False) to deactivate
the corresponding column identified in "override"

Signed-off-by: Alberto Pianon <alberto@pianon.eu>

aliens4friends/models/harvest.py

@@ -248,10 +248,10 @@ class Column(BaseModel):
     def __init__(
         self,
 		text: str,
-		value: str,
+		value: Union[str, bool], # false to deactivate an existing column
 		type: str,
 		tooltip: str,
-		override: str
+		override: str # position of the column to override (or deactivate)
 	):
         self.text = text
         self.value = value