This can be used to add service products in a quotation with a price of 0 which
will create a task in a project without showing them to the customer. This is
very useful when used in conjunction with product sets (see sale_product_set_layout).
The module also hides the lines from the invoice.
Installing this module does not enable sale layout. You need to activate it in the sales settings.
Then you can check the hidden field on sale layout categories. These categories will not be displayed.
Bugs are tracked on GitHub Issues. In case of trouble, please
check there if your issue has already been reported. If you spotted it first,
help us smash it by providing detailed and welcomed feedback.