Resource: `oxide_system_subnet_pool_silo_link`

[sudomateo]

Deprecate the oxide_subnet_pool_silo_link resource in favor of a new oxide_system_subnet_pool_silo_link resource with the following structure.

resource "oxide_system_subnet_pool_silo_link" "example" {
  pool = "my-pool"
  silo = "my-silo"
}

It will use the following Oxide APIs:

• Create: https://docs.oxide.computer/api/system_subnet_pool_silo_link
• Read: https://docs.oxide.computer/api/system_subnet_pool_silo_list (maybe)
• Update: https://docs.oxide.computer/api/system_subnet_pool_silo_update
• Delete: https://docs.oxide.computer/api/system_subnet_pool_silo_unlink