src: add detailed embedder process initialization API

doc/api/embedding.md

@@ -37,15 +37,18 @@ the `node` and `v8` C++ namespaces, respectively.
 int main(int argc, char** argv) {
   argv = uv_setup_args(argc, argv);
   std::vector<std::string> args(argv, argv + argc);
-  std::vector<std::string> exec_args;
-  std::vector<std::string> errors;
   // Parse Node.js CLI options, and print any errors that have occurred while
   // trying to parse them.
-  int exit_code = node::InitializeNodeWithArgs(&args, &exec_args, &errors);
-  for (const std::string& error : errors)
+  std::unique_ptr<node::InitializationResult> result =
+      node::InitializeOncePerProcess(args, {
+        node::ProcessInitializationFlags::kNoInitializeV8,
+        node::ProcessInitializationFlags::kNoInitializeNodeV8Platform
+      });
+
+  for (const std::string& error : result->errors())
     fprintf(stderr, "%s: %s\n", args[0].c_str(), error.c_str());
-  if (exit_code != 0) {
-    return exit_code;
+  if (result->early_return() != 0) {
+    return result->exit_code();
   }
 
   // Create a v8::Platform instance. `MultiIsolatePlatform::Create()` is a way
@@ -58,10 +61,13 @@ int main(int argc, char** argv) {
   V8::Initialize();
 
   // See below for the contents of this function.
-  int ret = RunNodeInstance(platform.get(), args, exec_args);
+  int ret = RunNodeInstance(
+      platform.get(), result->args(), result->exec_args());
 
   V8::Dispose();
   V8::DisposePlatform();
+
+  node::TearDownOncePerProcess();
   return ret;
 }
 ```