Add support for add/remove updates on list fields to MMv1

[rileykarson]

What kind of contribution is this issue about?

MMv1-based resource

Details

See #2570 for an example case. Note that even that is a complex case- there's a single method with conditions (only add or only remove, no mixing) rather than distinct methods that we can call.

We currently assume a resource has a standard update or each field a single custom update. With this change we'd support multiple calls depending on the exact change. This may be resolved by a new custom code injection point rather than full templating, given there are a small # of cases.

References

• Error updating secondary IP ranges in Google_compute_subnetwork  #2570

[rileykarson]

Note: We can always do custom_update, pre_update, and post_update in the meantime while this is not supported.