Extract T5 module and add main function to use it (#829)

* Extract t5 out of musicgen

* Add main for t5 module

candle-transformers/src/models/mod.rs

@@ -7,4 +7,5 @@ pub mod llama;
 pub mod quantized_llama;
 pub mod segment_anything;
 pub mod stable_diffusion;
+pub mod t5;
 pub mod whisper;