Break Circular Dependency between React-Codegen and React-Fabric (#36210)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/36210

One of the circular dependencies we have in OSS was between React-Codegen and React-Fabric.

React-Codegen generates component which has to depends on React-Fabric because they need to use the files contained in the `react/renderer/view` folder.

React-Fabric contains some components that depends on RNCore, which was generated inside the React-Codegen folder.

This change generates the RNCore components inside the `ReactCommon/react/renderer/components/rncore` folder, breaking the dependency as `rncore` folder is now contained by React-Fabric itself.

**Fun Fact:** That's how it always should have been. There was already a line in the `.gitignore` to exclude the content of `ReactCommon/react/renderer/components/rncore` folder. I guess that with some of the refactoring/previous projects on Codegen, this requirements has slipped.

## Changelog:
[iOS][Breaking] -  generates RNCore components inside the ReactCommon folder and create a new pod for platform-specific ImageManager classes

Reviewed By: sammy-SC, dmytrorykun

Differential Revision: D43304641

fbshipit-source-id: ebb5033ce73dbcd03f880c3e204511fdce04b816

scripts/codegen/generate-artifacts-executor.js

@@ -25,13 +25,16 @@ const RN_ROOT = path.join(__dirname, '../..');
 const CODEGEN_DEPENDENCY_NAME = '@react-native/codegen';
 const CODEGEN_REPO_PATH = `${RN_ROOT}/packages/react-native-codegen`;
 const CODEGEN_NPM_PATH = `${RN_ROOT}/../${CODEGEN_DEPENDENCY_NAME}`;
-const CORE_LIBRARIES = new Set(['rncore', 'FBReactNativeSpec']);
+const CORE_LIBRARIES_WITH_OUTPUT_FOLDER = {
+  rncore: path.join(RN_ROOT, 'ReactCommon'),
+  FBReactNativeSpec: null,
+};
 const REACT_NATIVE_DEPENDENCY_NAME = 'react-native';
 
 // HELPERS
 
 function isReactNativeCoreLibrary(libraryName) {
-  return CORE_LIBRARIES.has(libraryName);
+  return libraryName in CORE_LIBRARIES_WITH_OUTPUT_FOLDER;
 }
 
 function executeNodeScript(node, script) {
@@ -273,7 +276,6 @@ function handleInAppLibraries(
 }
 
 // CodeGen
-
 function getCodeGenCliPath() {
   let codegenCliPath;
   if (fs.existsSync(CODEGEN_REPO_PATH)) {
@@ -345,8 +347,10 @@ function generateCode(iosOutputDir, library, tmpDir, node, pathToSchema) {
   );
 
   // Finally, copy artifacts to the final output directory.
-  fs.mkdirSync(iosOutputDir, {recursive: true});
-  execSync(`cp -R ${tmpOutputDir}/* ${iosOutputDir}`);
+  const outputDir =
+    CORE_LIBRARIES_WITH_OUTPUT_FOLDER[library.config.name] ?? iosOutputDir;
+  fs.mkdirSync(outputDir, {recursive: true});
+  execSync(`cp -R ${tmpOutputDir}/* ${outputDir}`);
   console.log(`[Codegen] Generated artifacts: ${iosOutputDir}`);
 }