Remove UIImplementationProvider class and refactor UIManagerModule

Summary:
@public
This diff deprecates and deletes the UIImplementationProvider class.

It is not required to create an UIImplementation provider anymore, from now on the UIImplementation is created inside the UIManagerModule.

If you are using the UIImplementationProvider to create a ReactInstanceManager
e.g.:

```
    ReactInstanceManager =
        getReactInstanceManagerBuilder()
            ...
            .setUIImplementationProvider(...)
            ...
            .build();
```

Then you should just remove that line:
```
    ReactInstanceManager =
        getReactInstanceManagerBuilder()
            .set.....
            .build();
```

Reviewed By: achen1

Differential Revision: D8650376

fbshipit-source-id: 8d883295d8bf6578a99685edf6a2a84c6d0df0cf

ReactAndroid/src/main/java/com/facebook/react/ReactNativeHost.java

@@ -7,20 +7,16 @@
 
 package com.facebook.react;
 
-import com.facebook.react.bridge.JSIModulePackage;
-import javax.annotation.Nullable;
-
-import java.util.List;
-
 import android.app.Application;
-
 import com.facebook.infer.annotation.Assertions;
+import com.facebook.react.bridge.JSIModulePackage;
 import com.facebook.react.bridge.JavaScriptExecutorFactory;
 import com.facebook.react.bridge.ReactMarker;
 import com.facebook.react.bridge.ReactMarkerConstants;
 import com.facebook.react.common.LifecycleState;
 import com.facebook.react.devsupport.RedBoxHandler;
-import com.facebook.react.uimanager.UIImplementationProvider;
+import java.util.List;
+import javax.annotation.Nullable;
 
 /**
  * Simple class that holds an instance of {@link ReactInstanceManager}. This can be used in your
@@ -74,7 +70,6 @@ public abstract class ReactNativeHost {
       .setUseDeveloperSupport(getUseDeveloperSupport())
       .setRedBoxHandler(getRedBoxHandler())
       .setJavaScriptExecutorFactory(getJavaScriptExecutorFactory())
-      .setUIImplementationProvider(getUIImplementationProvider())
       .setJSIModulesPackage(getJSIModulePackage())
       .setInitialLifecycleState(LifecycleState.BEFORE_CREATE);
 
@@ -112,16 +107,6 @@ public abstract class ReactNativeHost {
     return mApplication;
   }
 
-  /**
-   * Get the {@link UIImplementationProvider} to use. Override this method if you want to use a
-   * custom UI implementation.
-   *
-   * Note: this is very advanced functionality, in 99% of cases you don't need to override this.
-   */
-  protected UIImplementationProvider getUIImplementationProvider() {
-    return new UIImplementationProvider();
-  }
-
   protected @Nullable
   JSIModulePackage getJSIModulePackage() {
     return null;