Added sqlite version check for returning statement

SQlite version check needs to be applied for the function insert_reference_entity just like it exists for the function insert_assessment. The reason is that older versions of sqlite within python does not understand the RETURNING statement.

\approve @ds @laurens @shinde

exposurelib/database.py

@@ -263,9 +263,9 @@ class AbstractExposure(AbstractDatabase, ABC):
         sql_statement = "INSERT INTO EntityReference "
         sql_statement += "(quadkey, country_iso_code, geom) "
         sql_statement += "VALUES ('%s', '%s', %s) " % (quadkey, country_iso_code, tile_geometry)
-        sql_statement += "RETURNING id"
         self.cursor.execute(sql_statement)
-        return self.cursor.fetchone()[0]
+        entity_id = self.get_reference_entity_id(quadkey=quadkey)
+        return entity_id
 
     def get_reference_entity_id(self, quadkey):
         """