"Sub-list" for resources with multiple primary identifiers

When a resource schema providers more than one property for `primaryIdentifier`, it may make sense to list the resources for a fixed value of one or more of those properties.

We're building an S3 bucket notification resource, to solve a [long-standing problem](https://read.acloud.guru/cloudformation-is-an-infrastructure-graph-management-service-and-needs-to-act-more-like-it-fa234e567c82). Each item in the notification configuration for a bucket is a separate resource. The `primaryIdentifier` is the combination of the bucket name and the notification configuration item id. The list handler handler will iterate over all buckets, returning all notification configuration items inside. But it's also sensible to think that a user could ask to list all notification resources for a fixed bucket name.

It seems likely that people will order their primary identifier list from general to specific, so may it could be automatic that if a list handler supports this "sub-listing" the user could provide the first value, the first and second, etc.

Review the resource schema's primaryIdentifier semantics and the list handler behavior described in the issue. Define how callers would supply progressively fixed identifier values, how providers advertise support for sub-listing, and what the resulting request and response behavior should be.

Written by the indexing model from the issue text.