Add baseline-profile

[oxyroid]

Summary

• Add BaselineProfileGenerator with Pixel5 Api31 AOSP system source image.
• Add ExampleStartupBenchmark so that you can easy test the app startup performance with or without baseline-prof.txt.
• Fix ignoring .idea folder because we need to store Gradle task configuration as project file.
• New Gradle task to generate new baseline files before each new version is released.
• Generate a baseline-prof.txt in my Xiaomi 11 Ultra smartphone.
• I have tested the app startup performance with- and without- baseline, here is the result:
  

Reference

https://developer.android.com/jetpack/compose/performance#use-baseline