* backend of add_scalars

* fix function name bug of get_scalars_tags

* @zh794390558 and @ShenYuhan commented 0508

* fix a bug

* adapt to frontend runs need

* fix proto

* fix a bug

* add scalars test demo

* fix

* adapt scalars to scalar

* remove unused code

* fix demo code

* fix proto version

* fix proto version

* upgrade protoc to v3.19.0

* fix a bug in logreader
Co-authored-by: N伽利略 <jialiasus2@163.com>
Co-authored-by: Nwuzewu <wuzewu@baidu.com>
Co-authored-by: N伽利略 <jialiasus2@163.com>
Co-authored-by: Nwuzewu <wuzewu@baidu.com>