[Feature] Add "Quantity" as an addable option

[DoktorShift]

Is your feature request related to a problem? Please describe.

Right now the extension behave options to trigger the device restricted by

1. Opening time
2. payable x times during the last 24 hours

Describe the solution you'd like

One more option to allow triggering by a quantity check would allow a few more usecases.

I would like it to be possible to specify the quantity of availability for each product/machine. That way, it can no longer be triggered if the product is sold out.

This would allow or improve the "misuse" of the extension, e.g. for the use of vending machines.

This is my solution

Add a "optional int" value field to specify the quantity during configuration/editing of the device.

Additional context

1. If the field is empty do not consider this option.
2. If value 0 give back sold out
3. if value <1 allow create invoice

[DoktorShift]

Thoughts

1. Backend Update:

   • Implement a feature in the backend to track the product's quantity. When the quantity reaches 0, mark the product as "sold out" in the database. This would prevent the device from being triggered when a product is out of stock.

2. UI Enhancement:

   • In the DeviceTimer configuration/editing form, add a visible field for the current product quantity.
   • When the quantity hits 0, display a prominent "Refill Needed" message with an option to manually restock the product. This would improve usability by enabling quick restocking directly through the UI.

3. WebSocket or Webhook Reminder:

   • Integrate a WebSocket/Webhook connection to send a reminder when the product quantity reaches 0. This could trigger notifications or alerts for admins.