Updated quantized phi model (#2099)

* Quantized phi in a separate file.

* Add the quantized phi example + rework the model code.

* Improve the phi model.

* Get some generation out.

* Use the appropriate rope shape.

* Tweak the default prompt.

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Co-authored-by: Jane Doe <jane.doe@example.org>

candle-transformers/src/models/mod.rs

@@ -37,6 +37,7 @@ pub mod quantized_mistral;
 pub mod quantized_mixformer;
 pub mod quantized_moondream;
 pub mod quantized_mpt;
+pub mod quantized_phi;
 pub mod quantized_recurrent_gemma;
 pub mod quantized_rwkv_v5;
 pub mod quantized_rwkv_v6;