Implementation of ASFormer (not fully completed)

[jts250]

Thanks for your contribution and we appreciate it a lot. The following instructions would make your pull request more healthy and more easily got feedback.
If you do not understand some items, don't worry, just make the pull request and seek help from maintainers.

Motivation

Implement ASFormer.

Modification

Adding configuration files, model files (ASFormer), dataset files, and evaluation metrics for inference of video action segmentation (not fully completed).

Notes

This branch is for the midterm defense and is not fully completed.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

---

ts seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}