Add support for lifecycle rules

[naseemkullah]

As per https://www.terraform.io/docs/providers/google/r/storage_bucket.html#lifecycle_rule

[morgante]

Currently we don't have support, we should add it!

Potential input:

module "gcs_buckets" {
  source  = "terraform-google-modules/cloud-storage/google"
  version = "~> 0.1"
  project_id  = "<PROJECT ID>"
  names = ["first", "second"]
  prefix = "my-unique-prefix"
  set_admin_roles = true
  admins = ["group:[email protected]"]
  versioning = {
    first = true
  }
  bucket_admins = {
    second = "user:[email protected],[email protected]"
  }
  lifecycle_rules = [{
    action = "SetStorageClass"
    storage_class = "COLDLINE"
    condition = {
      created_before = "2019-06-14"
    }
  }]
}