### What does this PR do?
To implement a purely asynchronous training workflow, we further split
the training process into a Trainer and a Rollouter based on the
existing one-step-off policy code, with samples transmitted via a
message queue.
We will continue to integrate partial rollout to mitigate the impact of
long-tail training.
> Add **concise** overview of what this PR aims to achieve or
accomplish. Reference related GitHub issues and PRs that help with the
review. https://github.com/volcengine/verl/pull/2231https://github.com/volcengine/verl/pull/2200
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---------
Co-authored-by: meituan-search <machi04@meituan.com>
Co-authored-by: wangshulin02 <wangshulin02@meituan.com>
Co-authored-by: arron <arron@MBP-2G17FXQ05P-2332.local>
Co-authored-by: wangshulin02 <953550366@qq.com>
Co-authored-by: hadoop-ai-search <hadoop-ai-search@set-zw04-mlp-codelab-pc1189.mt>
Co-authored-by: sl-1314 <82856253+sl-1314@users.noreply.github.com>
Co-authored-by: arron <arron@MBP-VH9RV7LTJC-1907.local>
Co-authored-by: arron <arron@MBP-JFQXPWR11F-1943.local>
