DevInfra enhancement

- monorepo?
- easily runnable build/test for modules/engines;
- following lang-specific style, e.g,
- `make & make test` for c++, `mvn package` & `mvn test` for java, `cargo test` for rust ....
- it would be better if every developer could run the whole pipeline of CI on local/dev-env;
- coverage for repo, not only for python code;
- management
- github @/cc overlook -> instant notification?
- naming
- two coordinators, confusing?
- preserving MaxGraph in GAIA? if no, consider before re-introducing `com.alibaba.maxgraph.xxxx`