[Feature]KTN

[65456u]

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Description

Added [KTN](https://arxiv.org/abs/2203.02018).

Checklist

Please feel free to remove inapplicable items for your PR.

• [x] The PR title starts with [$CATEGORY] (such as [NN], [Model], [Doc], [Feature]])
• [x] Changes are complete (i.e. I finished coding on this PR)
• [x] All changes have test coverage
• [x] Code is well-documented
• [x] To the best of my knowledge, examples are either not affected by this change, or have been fixed to be compatible with this change
• [x] Related issue is referred to in this PR
• [x] If the PR is for a new model/paper, I've updated the example index [here](../README.md).

Changes

• Added Model HMPNN for experimenting in KTN
• Added OAG_CS dataset for baseline testing
• Added task KTN and re-implemented NDCG and MRR metrics
• Added KTN trainer flow for node classification