### What changes were proposed in this pull request?
This PR adds CMakeList structure and ProcessBase utils code to CppClient.
### Why are the changes needed?
To organize the compiling structure and to provide ProcessBase utils.
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
Compilation.
Closes#2940 from HolyLow/issue/celeborn-1741-add-processbase-utils-to-cppClient.
Authored-by: HolyLow <jiaming.xie7@gmail.com>
Signed-off-by: mingji <fengmingxiao.fmx@alibaba-inc.com>
