dashboard integration - output training perf metrics as json (#3809)
* dashboard integration - first phase
* change a field
* perf scripts
* addressing PR comments
* address comments and fix build
* minor
* make GetConfigFromData() const
* more update for comments
* addressing comments
* more on addressing comments
* minor
* fix build
* add condition check
* more on comments
* retrun status
* remove batch size
* on comments
* rename pkg path
* rename pkg path
* additional commentss
Co-authored-by: Ethan Tao <ettao@microsoft.com>