### What this PR does / why we need it?
Add muls_add triton kernel with related fusion pass. What's more, this
PR refactors `AscendCompilationConfig` and delete `NpugraphExConfig`.
### Does this PR introduce _any_ user-facing change?
None
### How was this patch tested?
CI passed with new added test.
- vLLM version: v0.13.0
- vLLM main:
45c1ca1ca1
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Signed-off-by: whx-sjtu <2952154980@qq.com>
### What this PR does / why we need it?
As part of the preparation work for the
[RFC](https://github.com/vllm-project/vllm-ascend/issues/6214)
We have added a documentation about npugraph_ex, which mainly explains
and introduces its usage and FX graph optimization.
The introduction to FX graph optimization also includes specific
explanations of the default passes, the implementation methods for
custom fusion passes, and how to capture the FX graph during the
optimization process through environment variable configuration.
---------
Signed-off-by: chencangtao <chencangtao@huawei.com>
Co-authored-by: chencangtao <chencangtao@huawei.com>
