Support SSDK generation via DirectedCodegen

The 2 SmithyBuildPlugins have duplication, which can be reduced via refactoring

Ran `yarn generate-clients -s && yarn test:server-protocols` in aws-sdk-js-v3
with this commit. Compared the generated ssdks with
https://github.com/gosar/aws-sdk-js-v3/tree/f47b48a1eb1187657f489b4e041f979e72e0134d
and found there were differences but only some moving around of code within
some files.

Author: gosar

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/DirectedTypeScriptCodegen.java

@@ -74,7 +74,7 @@ final class DirectedTypeScriptCodegen
 
     @Override
     public SymbolProvider createSymbolProvider(CreateSymbolProviderDirective<TypeScriptSettings> directive) {
-        return new SymbolVisitor(directive.model(), directive.settings());
+        return directive.settings().getArtifactType().createSymbolProvider(directive.model(), directive.settings());
     }
 
     @Override

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/TypeScriptCodegenPlugin.java

@@ -49,10 +49,8 @@ public void execute(PluginContext context) {
         runner.model(context.getModel());
 
         // Create the TypeScriptSettings object from the plugin settings.
-//        TypeScriptSettings settings = runner.settings(TypeScriptSettings.class, context.getSettings());
-        TypeScriptSettings settings = TypeScriptSettings.from(context.getModel(), context.getSettings());
-//        TypeScriptSettings settings = TypeScriptSettings.from(context.getModel(), context.getSettings(),
-//                TypeScriptSettings.ArtifactType.CLIENT);
+        TypeScriptSettings settings = TypeScriptSettings.from(context.getModel(), context.getSettings(),
+                TypeScriptSettings.ArtifactType.CLIENT);
         runner.settings(settings);
 
         runner.service(settings.getService());

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/TypeScriptServerCodegenPlugin.java

@@ -17,7 +17,8 @@
 
 import software.amazon.smithy.build.PluginContext;
 import software.amazon.smithy.build.SmithyBuildPlugin;
-import software.amazon.smithy.typescript.codegen.TypeScriptSettings.ArtifactType;
+import software.amazon.smithy.codegen.core.directed.CodegenDirector;
+import software.amazon.smithy.typescript.codegen.integration.TypeScriptIntegration;
 import software.amazon.smithy.utils.SmithyInternalApi;
 
 /**
@@ -33,6 +34,32 @@ public String getName() {
 
     @Override
     public void execute(PluginContext context) {
-        new CodegenVisitor(context, ArtifactType.SSDK).execute();
+        CodegenDirector<TypeScriptWriter, TypeScriptIntegration, TypeScriptCodegenContext, TypeScriptSettings> runner
+                = new CodegenDirector<>();
+
+        runner.directedCodegen(new DirectedTypeScriptCodegen());
+
+        // Set the SmithyIntegration class to look for and apply using SPI.
+        runner.integrationClass(TypeScriptIntegration.class);
+
+        // Set the FileManifest and Model from the plugin.
+        runner.fileManifest(context.getFileManifest());
+        runner.model(context.getModel());
+
+        // Create the TypeScriptSettings object from the plugin settings.
+        TypeScriptSettings settings = TypeScriptSettings.from(context.getModel(), context.getSettings(),
+                TypeScriptSettings.ArtifactType.SSDK);
+        runner.settings(settings);
+
+        runner.service(settings.getService());
+
+        // Configure the director to perform some common model transforms.
+        runner.performDefaultCodegenTransforms();
+
+        // TODO: How is smithy-typescript currently dealing with no input/output?
+//        runner.createDedicatedInputsAndOutputs();
+
+        // Run it!
+        runner.run();
     }
 }