generate resource shape 'properties' with Smithy IDL serialization

[zourzouvillys]

Adds support for outputting properties for resources in the Smithy IDL model serializer.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[kstich]

Thanks for catching this! If you'd like to take it to completion, can you add some valid resource properties to this test file? We can add the test cases if you'd prefer, just let us know.

[zourzouvillys]

added.

upon modifying the service-shapes.smithy file to just include properties within MyResource without adding new operations, i encountered validation failures unrelated to this specific change that look like they should have been getting triggered and weren't. adding the properties results in validation (correctly?) failing because the id was not @required.

if i'm not missing something here, happy to investigate separately from this PR, and/or open an issue.