This is to be used for stack of switches only

- a stack_member is linked to an host (device_type has to be "Switch")
- a stack_member is an integer between 0 and 9 (included) or can be None
- the couple (host_id, stack_member) must be unique

JIRA INFRA-267

If we scroll to the submit button, we can't see the "Submit" QRCode

The QRCode content doesn't matter. It's only there to trigger a CR to
submit the form.
Scanning a serial number will focus on the submit button so that
scanning the QRCode doesn't enter text in any form input field.

We don't want to submit the form when scanning a code bar or ICS id.
In keyboard mode, the scanner sends a CR as last character.

Allow to use a scanner configured as keyboard to register items
via the web UI.
1. The attributes should be selected manually
2. Focus set manually on ICS id
3. Scan an ICS id -> prefix removed and focus set to serial number
4. Scan serial number
5. Click on submit
6. Focus set automatically on ICS id
7. Repeat from 3