Smithy generator for paginator

[kai-ion]

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Description of changes:
Smithy-based code generator for paginators

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[agicquelamz]

Why do we need this? It's not like we're going to be using smithy based endpoints rule traits right?

[kai-ion]

Ah, this was from copying the pattern used in our codegen-workshop.
I will refactor the build script to use our existing pattern from smoke-test gen

[kai-ion]

Smithy actually needs all the above dependencies, in the current set up we are not accepting any unknown traits

[sbiscigl]

nit: validate that

for (cont auto& pageIter: paginator) {
  ...
}

works as that is the most idomatic way people will likely use this

[sbiscigl]

make this static/immtuable list, we dont want to re-create this everytime we call the function, this list will never change at runtime

[kai-ion]

Okay I made it immutable with final and initialized in the constructor, this way we only re-create this once per service generation and not once per trait generation
private final List<TokenResolver> resolvers; initialized in the constructor

[sbiscigl]

premature returning is anti patter lets make this a a stream

resolvers.stream()
                .filter(resolver -> resolver.canResolve(token, op))
                .findFirst()
                .ifPresentOrElse(resolver -> resolver.writeLogic(writer, token, op),
                        () -> {
                            // Fallback
                            if (ShapeUtil.hasTopLevelMember(context.getModel(), op, "IsTruncated")) {
                                writer.write("        return result.GetIsTruncated();");
                            } else {
                                writer.write("        return false;");
                            }
                        });

potentially refactoring the fallback method to a private function

[kai-ion]

Made it into a stream instead of early return.
Not sure if we need to refactor it to a private function though, its only used in this specific case.

[sbiscigl]

approved, try to address the left over comments as you fix the build