[MXNET-1418]Add contrib op into cpp package

Description

Hi, there. I add the contrib operators into cpp-package. The prefix of their name is _. For example, the name of ROIAlign is _contrib_ROIAlign. The number of lines of cpp-package/include/mxnet-cpp/op.h is around 30 thousand after this PR, 16 thousand before this PR. I'm not sure whether to divide the contribution operators into a new header file, like contrib_op.h.

Checklist

Essentials

Please feel free to remove inapplicable items for your PR.

• [x] The PR title starts with [MXNET-$JIRA_ID], where $JIRA_ID refers to the relevant JIRA issue created (except PRs with tiny changes)
• [x] Changes are complete (i.e. I finished coding on this PR)
• [ ] All changes have test coverage:
• Unit tests are added for small changes to verify correctness (e.g. adding a new operator)
• Nightly tests are added for complicated/long-running ones (e.g. changing distributed kvstore)
• Build tests will be added for build configuration changes (e.g. adding a new build option with NCCL)
• [x] Code is well-documented:
• For user-facing API changes, API doc string has been updated.
• For new C++ functions in header files, their functionalities and arguments are documented.
• For new examples, README.md is added to explain the what the example does, the source of the dataset, expected performance on test set and reference to the original paper if applicable
• Check the API doc at http://mxnet-ci-doc.s3-accelerate.dualstack.amazonaws.com/PR-$PR_ID/$BUILD_ID/index.html
• [x] To the my best knowledge, examples are either not affected by this change, or have been fixed to be compatible with this change

Changes

• [x] update dmlc-core for adding the type name of dim_t (int64_t). https://github.com/dmlc/dmlc-core/pull/540
• [x] support type name for mxnet::Tuple<T>
• [x] support more data types and add more operators in cpp-package/scripts/OpWrapperGenerator.py

Comments

• If this change is a backward incompatible change, why must this change be made.
• Interesting edge cases to note here

@wkcn Could you please resolve the merge conflicts? @nswamy @anirudh2290 @eric-haibin-lin Could you please review the PR? Thanks!

I have updated dmlc-core, but the CI failed in MXNet Scala binding.

I don't know how to solve the issue about Scala binding. Does anyone help me address the problem? Thank you!