[EP ABI] Add documentation for OrtValue and ort_graph_to_proto util #2660

Job	Run time
2. Build Minimal (Exceptions Disabled)	10m 4s
4. Build Minimal (Globally Allowed Types)	7m 55s
5. Build Extended Minimal	10m 50s
1. Build Full ORT and Generate ORT Files	15m 53s
6a. Build Regular (No Optional Features)	13m 44s
6b. Build Minimal (No Optional Features)	8m 39s
6c. Build Extended Minimal (No Optional Features)	9m 7s
3b. Build Minimal (Type Reduction)	7m 39s
3a. Build Minimal (Custom Ops)	7m 33s
7. Build Extended Minimal (Android NNAPI)	8m 0s
	1h 39m 24s

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