Add Ascend NPU support for veRL

[Yikun]

This RFC proposed to provide initial support for veRL on Ascend NPU.

PR1：Support FSDP worker and vLLM Ascend #332

A basic PR based on FSDP and Ascend NPU to make GRPO workflow work on Ascend NPU
(based on #198 which is proposed by @Chendong98 )

Include Single controller, FSDP worker Ascend NPU support, vLLM Ascend support (>=0.7.1)

Co-author:

• @as12138 (FSDP worker / vLLM Ascend)
• @Chendong98(Single controller)
• @celestialli (vLLM Ascend)

PR2：Support Megatron 0.6 in veRL #85

Owner: @Chendong98

PR3: Support MindSpeed worker in veRL TBD

Based on PR2
Owner: @Chendong98

[Yikun]

We had a internal meeting about Ascend NPU support for veRL, above is the initial info to make things clear for several PRs recent submitted (#332 #198 #85), hopes no more misunderstanding.