Make network interfaces a list

variable "network_interfaces" {
  type = list(object({
    name = optional(string)
    network_id = optional(string)
    network_name = optional(string)
    macvtap = optional(string)
    hostname = optional(string)
    wait_for_lease = optional(bool)

    dhcp = optional(bool)
    ip = optional(string)
    gateway = optional(string)
    nameservers = optional(list(string))
    mac = optional(string)

    additional_routes = optional(list(object({
      network = string
      gateway = string
    })))
  }))
  default = []