[FEATURE] A universal design of code review workflow

[crystaldust]

There are many different forms of code review/merging/maintaining mechanisms in opensource community. Like Apache foundation's incubation system; Linux kernel's mailing list discussion and patch review/merging; GitHub/GitLab's issue/PR/comments discussion collaboration. So we need to design a universal code review workflow, which obtains the whole process of code being written, discussed/reviewed, modified, and merged, then different code collaboration systems can be applied to the universal template. And any future forms can be adapted.