Add functionality to recreate a smithy model from smithy4s schemas/services

[lewisjkl]

Adds the capability to translate a smithy4s service or schema to the corresponding smithy model object (from the smithy model library). This lives in the dynamic module and will be useful for testing and other purposes in the future.

PR Checklist (not all items are relevant to all PRs)

• Added unit-tests (for runtime code)
• Added bootstrapped code + smoke tests (when the rendering logic is modified)
• Added build-plugins integration tests (when reflection loading is required at codegen-time)
• Added alloy compliance tests (when simpleRestJson protocol behaviour is expanded/updated)
• Updated dynamic module to match generated-code behaviour
• Added documentation
• Updated changelog

[lewisjkl]

Will update changelog and add documentation tomorrow, but wanted to put this up so people could take a look at what I have so far.