Complete Construct Model

## Description
It’s clear that constructs are imperative to the CDK experience. We repeatedly hear from CDK builders that the most important improvement that the CDK can make for its construct experience would be to provide greater service coverage. Because of this, the CDK team is investigating how we can provide more comprehensive AWS service coverage. In the past, the CDK has relied on community and in-house authored constructs to address construct demand. In the future, our goal is to bring CDK builders a complete and consistent construct model through largely autogenerated means. This model would provide builders with Day 1 support of AWS services--the moment services are launched--complete with the features that builders love in their L2s. As we are investigating this effort, it’s possible that there will be gradual rollouts for us to realize this goal. If you have any feedback or comments on this, we would highly appreciate you sharing them as a comment within this RFC.

Start by reading the RFC description and its existing comment thread. No files, tests, or implementation entry points are named; the issue asks for feedback on a possible autogenerated construct model and gradual rollout, so completion criteria are not defined in the payload.

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