Author the user story for this feature

As an Android developer, I want the documentation to clearly explain how to enable smart flank for Android.

Describe the solution you'd like
After exploring the source code, I found the config need to fulfill two requirements:

• Set a valid value to smart-flank-gcs-path
• Set either the legacy-junit-result or full-junit-result to be true

It would be better if the document could state these two points.😀