Add infrastructure for auto EP selection (#24430)
### Description
<!-- Describe your changes. -->
Add infrastructure to enable auto EP selection.
Device discovery for CPU/GPU/NPU on Windows.
Supports internal (CPU/DML/WebGPU) and provider bridge (CUDA) EPs
currently.
Infrastructure will be used with plugin EPs next.
Selection policy implementation will be added next, so in the interim
there's a temporary function with manually specified selection so unit
tests can cover the end-to-end.
### 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. -->
---------
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Adrian Lizarraga <adlizarraga@microsoft.com>
