Add Text-To-Speech pipeline (#24952)

* add AutoModelForTextToSpeech class

* add TTS pipeline and tessting

* add docstrings to text_to_speech pipeline

* fix torch dependency

* corrector 'processor is None' case in Pipeline

* correct repo id

* modify text-to-speech -> text-to-audio

* remove processor

* rename text_to_speech pipelines files to text_audio

* add textToWaveform and textToSpectrogram instead of textToAudio classes

* update TTS pipeline to the bare minimum

* update tests TTS pipeline

* make style and erase useless import torch in TTS pipeline tests

* modify how to check if generate or forward in TTS pipeline

* remove unnecessary extra new lines

* Apply suggestions from code review

Co-authored-by: Sanchit Gandhi <93869735+sanchit-gandhi@users.noreply.github.com>

* refactor input_texts -> text_inputs

* correct docstrings of TTS.__call__

* correct the shape of generated waveform

* take care of Bark tokenizer special case

* correct run_pipeline_test TTS

* make style

* update TTS docstrings

* address Sylvain nit refactors

* make style

* refactor into one liners

* correct squeeze

* correct way to test if forward or generate

* Update output audio waveform shape

* make style

* correct import

* modify how the TTS pipeline test if a model can generate

* align shape output of TTS pipeline with consistent shape

---------

Co-authored-by: Sanchit Gandhi <93869735+sanchit-gandhi@users.noreply.github.com>

docs/source/en/main_classes/pipelines.md

@@ -318,6 +318,13 @@ Pipelines available for audio tasks include the following.
     - __call__
     - all
 
+### TextToAudioPipeline
+
+[[autodoc]] TextToAudioPipeline
+    - __call__
+    - all
+
+
 ### ZeroShotAudioClassificationPipeline
 
 [[autodoc]] ZeroShotAudioClassificationPipeline