### What this PR does / why we need it?
Mooncake layerwise connector supports Mamba prefix caching on prefiller
nodes.
### Does this PR introduce _any_ user-facing change?
Yes. Use `--enable-prefix-caching` and `--mamba-cache-mode align` to
enable mamba align mode prefix caching on P/D prefill nodes. This
function does not supports on decode nodes now.
### How was this patch tested?
By P/D E2E test.
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Signed-off-by: nwpu-zxr <zhouxuerong2@huawei.com>