[Native Lib] Support specifying LLaVA native library path

[AsakusaRinne]

NativeLibraryConfig.Instance.WithLibrary provides a way for user to specify the native library to be loaded directly. However, it cannot deal with LLaVA. Currently, users could specify NativeLibraryConfig.Instance.WithLibrary("llama.dll") but not NativeLibraryConfig.Instance.WithLibrary("llava_shared.dll"). With the introduce of LLaVA support in v0.11.1, this feature means a lot to users.

When adding this feature, extensibility should be considered because there is probably other cases just like LLaVA in the future.