[ARM] MatMulNBits Fp16 support - API change only (#22826)
### Description
A break-down PR of https://github.com/microsoft/onnxruntime/pull/22651
Op API change only.
- add template to functions and classes that support fp32 and fp16
- rename functions, classes and files that support fp32 and fp16 from
SQNBxxx to QNBxxx
### Motivation and Context
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- If it fixes an open issue, please link to the issue here. -->
