Deprecate the use of inventory items

[jeremystretch]

Proposed Changes

Deprecate the use of inventory items and, by extension, inventory item roles.

Justification

FRs #19001 and #19002 propose several improvements to modules that will eclipse the functionality provided by inventory items. Once implemented, we'll no longer need the inventory item model to track FRU hardware.

Impact

Users who employ inventory items today are encouraged to begin transitioning to using models instead. We may be able to provide some automated tooling to assist in this process. The removal of inventory items and roles will be planned for a future release.

[ITJamie]

this is a pretty big change for those of use using inventory items to track hdd/sdd's, memory etc.
how long of an overlap window is being proposed?

i agree that its probably the right path in the long term, but for those of us leveraging inventory items as they stand and using plugins like netbox-inventory which link inventory purchases to inventory items it would be good to have an idea of how long we have to migrate and to refactor tooling.

screenshots attached of an example of our current setup which i believe will migrate over

[jeremystretch]

To be clear, this is merely marking the functionality as deprecated. I would expect that it would not actually be removed from NetBox for several minor releases (probably around a year or so) to afford plenty of time to migrate to using modules.