Introduce ReactNativeConfiguration to manage experimentation

Summary: Similar to ComponentsConfiguration used by Litho. Allows us to abtest without having to pipe everything through ReactInstanceManager

Reviewed By: axe-fb

Differential Revision: D9930707

fbshipit-source-id: 43edf7d8fa2bab7b7888df57ea1bec2b4726f51b

ReactAndroid/src/main/java/com/facebook/react/config/BUCK

@@ -0,0 +1,11 @@
+load("//tools/build_defs/oss:rn_defs.bzl", "rn_android_library")
+
+rn_android_library(
+    name = "config",
+    srcs = glob(["**/*.java"]),
+    visibility = [
+        "PUBLIC",
+    ],
+    deps = [
+    ],
+)

ReactAndroid/src/main/java/com/facebook/react/config/ReactFeatureFlags.java

@@ -0,0 +1,17 @@
+package com.facebook.react.config;
+
+/**
+ * Hi there, traveller! This configuration class is not meant to be used by end-users of RN. It
+ * contains mainly flags for features that are either under active development and not ready for
+ * public consumption, or for use in experiments.
+ *
+ * These values are safe defaults and should not require manual changes.
+ */
+public class ReactFeatureFlags {
+
+  /**
+   * Whether we should load a specific view manager immediately or when it is accessed by JS
+   */
+  public static boolean lazilyLoadViewManagers = false;
+
+}