Task/749 **BREAKING CHANGE** - Change IPv6 role strings in apstra_datacenter_resource_pool_allocation resource

[chrismarget-j]

This PR changes the set of valid strings for the apstra_datacenter_resource_pool_allocation resource's role attribute.

The following strings have been replaced for consistency with the many other valid values which put ipv6 at the end:

• ipv6_spine_leaf_link_ips --------> spine_leaf_link_ips_ipv6
• ipv6_spine_superspine_link_ips -> spine_superspine_link_ips_ipv6
• ipv6_to_generic_link_ips---------> to_generic_link_ips_ipv6

After upgrading to a provider release which includes this change, the terraform provider will no longer accept the old strings. A validation error will require the configuration to be amended to use these new values.

After the configuration has been updated to use the new values, Terraform will plan a change, but the change should be nondisruptive to the blueprint. Notice this resource is being updated in-place, and the only attribute subject to change is role:

Terraform will perform the following actions:

  # apstra_datacenter_resource_pool_allocation.spine_leaf_link_ips_ipv6 will be updated in-place
  ~ resource "apstra_datacenter_resource_pool_allocation" "spine_leaf_link_ips_ipv6" {
      ~ role         = "ipv6_spine_leaf_link_ips" -> "spine_leaf_link_ips_ipv6"
        # (2 unchanged attributes hidden)
    }

Details of what's in this PR:

• purged some placeholder stuff related to Freeform blueprints (this isn't going to happen)
• the role attribute's RequiresReplace plan modifier has been changed to RequiresReplaceIf with a helper function which recognizes the old and new strings: No replace when updating role from an old style value to a new style value.
• rosetta module required to bring the new values to life
• a couple of overlooked test cases related to apstra.InterfaceNumberingIpv4Type and apstra.InterfaceNumberingIpv6Type which were required to get the rosetta tests passing

Closes #749