Change Equinix Metal Terraform provider to equinix/equinix

[xmudrii]

Description of the feature you would like to add / User story

The provider that we use at the moment, equinix/metal, has been deprecated as of July 1, 2023:

│ Equinix Metal Provider is now Deprecated (End-of-Life scheduled for July 1, 2023) meaning that this software is only supported or maintained by Equinix Metal and its community in a
│ case-by-case basis. The Equinix provider (https://registry.terraform.io/providers/equinix/equinix/latest/docs) has full support for existing Terraform managed Metal resources once
│ Terraform configuration and state are adapted. The Equinix provider manages resources including Network Edge and Fabric in addition to Metal. Please review the Metal to Equinix provider
│ migration guide: https://registry.terraform.io/providers/equinix/equinix/latest/docs/guides/migration_guide_equinix_metal

More details: https://registry.terraform.io/providers/equinix/equinix/latest/docs/guides/migration_guide_equinix_metal

Solution details

• Migrate to the supported Equinix Metal provider

Additional information

This requires migrating existing resources, i.e. we should document how to do this as part of the upgrade guide. We had something similar before for migration from Packet to Equinix Metal.