* add TracerUtil

* Interceptor ok

* add handler

* add context

* minor update

* keep span in trace context

* add span in search okay

* Update Context.cpp

* refactor

* refactor

* refactor

* format

* add context in SearchJob

* trace search okay

* add back finish span in interceptor

* add namespace

* add tracing config in server config

* add random id

* debug mode okay

* update CMakeLists

* add opentracing to cmake

* update unittest

* add tracing namespace

* remove std::run_time error

* add lock when erasing context_map

* update tracing config

* lint

* update CHANGELOG

* small fix

* fix server unit test

* fix scheduler unit test

* fix db unit test

* lint

* fix db unit test gpu version

* rename to tracing_config

* fix

* update

* trigger ci