feat(vpc): add support for ResourceIdentity

[yfodil]

Import can be done by identity now:

import {
  to       = scaleway_vpc.main
  identity = {
    id     = "11111111-1111-1111-1111-111111111111"
    region = "fr-par"
  }
}


resource "scaleway_vpc" "main" {}

[jremy42]

Isn't there a way to make a global function, since it'll basically be the same across all resources, right?