[Text Gen UX] Add prompt as input param alias (#1270)

from internal specs:

```python
text_pipeline = TextGeneration(model=MODEL, **kwargs)
text_result = text_pipeline(prompt=PROMPT, **kwargs)
```

src/deepsparse/transformers/pipelines/text_generation.py

@@ -83,6 +83,7 @@ class Config:
         arbitrary_types_allowed = True
 
     sequences: Union[str, List[str]] = Field(
+        alias="prompt",
         description="The input sequences to generate the text from.",
     )
     include_prompt_logits: bool = Field(