Add usage statistics for UI Unit testing and End-to-End testing

[mshabarov]

Add a usage statistics to TestBench for collecting the usage of UI Unit testing features and End-to-End testing features.
This was drafted in #1587, but doesn't work because of #1587 (comment) .

Possible solution is to add usage statistics of TB to the platform, where both TB modules and Flow modules are available (not tested yet).