Convert server to an Android project

To simplify the device server-side build, use gradle to create an APK,
even if we use it as a simple jar, by running its main() method.

server/src/main/java/com/genymobile/scrcpy/wrappers/ServiceManager.java

@@ -0,0 +1,40 @@
+package com.genymobile.scrcpy.wrappers;
+
+import android.os.IBinder;
+import android.os.IInterface;
+
+import java.lang.reflect.Method;
+
+public class ServiceManager {
+    private final Method getServiceMethod;
+
+    public ServiceManager() {
+        try {
+            getServiceMethod = Class.forName("android.os.ServiceManager").getDeclaredMethod("getService", String.class);
+        } catch (Exception e) {
+            throw new AssertionError(e);
+        }
+    }
+
+    private IInterface getService(String service, String type) {
+        try {
+            IBinder binder = (IBinder) getServiceMethod.invoke(null, service);
+            Method asInterfaceMethod = Class.forName(type + "$Stub").getMethod("asInterface", IBinder.class);
+            return (IInterface) asInterfaceMethod.invoke(null, binder);
+        } catch (Exception e) {
+            throw new AssertionError(e);
+        }
+    }
+
+    public WindowManager getWindowManager() {
+        return new WindowManager(getService("window", "android.view.IWindowManager"));
+    }
+
+    public DisplayManager getDisplayManager() {
+        return new DisplayManager(getService("display", "android.hardware.display.IDisplayManager"));
+    }
+
+    public InputManager getInputManager() {
+        return new InputManager(getService("input", "android.hardware.input.IInputManager"));
+    }
+}