feat: Deprecate `datasets` module, rename to `inferences` (#2785)

* Initial refactor of Datasets -> Inferences

* Add deprecation warnings to "datasets" public interface

* Fix type signature

* Ensure ExampleDatasets still exists

* Use multiline string

* Rename test files

* Remove test for `Inference.from_open_inference`

* exclude manual instrumentation example from type checks

* Revert changes to notebooks

* Rename `Inference` -> `Inferences`

* Fix line length

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Co-authored-by: Alexander Song <axiomofjoy@gmail.com>