feat: 添加FPS插件，显示帧率

src/plugins/fps/index.ts

@@ -0,0 +1,5 @@
+export * from './shared';
+export { default as showFps } from './showFps';
+export { default as hideFps } from './hideFps';
+export { default as showFpsPlugin } from './export_show';
+export { default as hideFpsPlugin } from './export_hide';