Migrate from RedHatSI/Packet to Equinix Metal

[displague]

This Terraform module was originally https://github.com/RedHatSI/terraform-packet-openshift.

This fork of the project migrates all Packet references, including Terraform resources, to use Equinix Metal branding and Terraform resources.

This migration also seeks to further modularize components of the module (DNS) and bring other enhancements (dynamic SSH Keys) found in other Equinix Metal modules: https://registry.terraform.io/namespaces/equinix

These goals are inline with RedHatGov/terraform-packet-openshift#46. At the end of this migration, this module will be published to the Terraform Registry.

This issue will not deal with the migration of existing deployments. We can explore that in a new issue, if raised.