[RFC]: Refactor torchair in vllm-ascend

[shen-shanshan]

Roadmap

Refactor the code of torchair in worker and model_runner: @wangxiyuan

• [1/4][Refactor] Refactor torchair worker #1885
• [2/4][Refactor] Refactor torchair utils #1892
• [Misc]: Torchair model runner refactor workflow #2203

Refactor the code of torchair in attention: @shen-shanshan

• [1/N][Refactor] Refactor AscendMetaData comments to make it clearer #1967
• [2/N][Refactor] Refactor V1 attention for better extensibility #1995
• [3/N][Refactor] Move torchair_attention to torchair dir #2017
• [4/N][Refactor] Refactor AscendAttentionMetadataBuilder for better extensibility and make the builder class of torchair extend from it #2375
• [5/N][Refactor] Make AscendAttentionTorchairBackendImpl extend from AscendAttentionBackendImpl #2495