[t5 optimization] kernel changes to t5 (#14928)
### Description
<!-- Describe your changes. -->
1. support optional bias in Attention op (used in T5 encoder)
2. support broadcasting rel_pos_bias in attention_softmax.h
3. add scale in
MHA op's attributes
4. support past_key/past_value and present_key/present_value in MHA
5. UT and parity tests are added
6. fix an issue: https://github.com/microsoft/onnxruntime/issues/14920
note: the fusions will be in another PR since mt5 needs to be tested and
an issue from github will be investigated.
Future works:
1. support shared buffer for past/present
2. enable trt kernels when possible and investigate (trt/cutlass)kernels
with rel_pos_bias)
3. support KV/QKV packing with past/present
### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->
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Co-authored-by: Ubuntu <wy@v100-2.0cdb2e52twzevn1i4fi45bylyg.jx.internal.cloudapp.net>
