Fcos cpp code review.
1、remove unused code.
2、Refactor SampleProcess and meet the following requirements. Please refer to pointpillar-cpp repo:  ​http://123.60.154.11/jac-soc/point_pillar_cpp/-/tree/mdc.develop, mdc.develop branch.
Clarify the function of SampleProcess: used to process the whole pipeline of fcos3d algorithm,including preprocess、model inference、postprocess and so on. Named Fcos3dPipeline.
Set public interface:
Init(parameters):this function is used to read cofig parameters from config file, load fcos3d model and other initialization operatations (for example: initialize ACL resource 、allocate memory for input output tensor of model.) and so on.
Process(image, results): this function is used to process image data,including preprocessing, model inference,postprocessing,etc. image: the input image data. results: the results of the whole processing.
3、Pay attention to coding style
code structure: Limit lines to 80 characters,Avoid global variables as much as possible, prefer local variables.
Indentation and Spaces: Leave spaces around binary operators.
4、It is recommended to use aipp to replace crop, padding, normalization and other operations in pre-processing.