onnxruntime

Re-organize the transpose optimization and layout transformation files. (#16246)

### Description
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Split out the more basic changes from #15552 for easier review.

Re-organize to clarify the structure
- Separate out generic base functionality from ORT specific components
  - pass in handlers for internal ORT ops to Optimize
- Split out layout transformation from transpose optimization
- Separate out level 1 transpose optimizer
- Cleanup some naming to try and clarify things like an optimizer vs.
general optimization code

Most of the changes are from this movement of code.

Two implementation changes:
- the extended handlers are queried first in GetHandler
- allows the extended handlers to override the default behaviour for an
ONNX operator
- simplify the Optimize function to remove OptimizerMode. 
- `can_modify_node` is used instead of `mode` and
`ignore_assigned_nodes` and a long description of the current usage is
added. I don't _think_ that changes the current behavior and hopefully
clarifies what happens and when, and makes the base transpose optimizer
implementation more generic.

### 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. -->
Create a cleaner separation to support adding EP specific logic next to
cleanly handle where an EP has additional layout sensitive behaviour
required (e.g. it's Resize implementation only handles one layout).