Add Speaker Diarization and Verification heads (#14723)

* Models

* Squashed commit of the following:

commit 72278e1e931a16d0879acc77f65762f3364833d0
Author: anton-l <aglozhkov@gmail.com>
Date:   Fri Dec 10 21:45:08 2021 +0300

* Add unispeech heads

* Add sd/sv automodels

* Docs cleanup

* Fix docstrings

* rename xvector classes

* examples

* Tests cleanup

* Style

* Better checkpoints for tests

* leftover docs

* apply review suggestions

* Style + init tests

* Update unispeech-sat tdnn downsampling

utils/update_metadata.py

@@ -74,6 +74,12 @@ PIPELINE_TAGS_AND_AUTO_MODELS = [
         "MODEL_FOR_NEXT_SENTENCE_PREDICTION_MAPPING_NAMES",
         "AutoModelForNextSentencePrediction",
     ),
+    (
+        "audio-frame-classification",
+        "MODEL_FOR_AUDIO_FRAME_CLASSIFICATION_MAPPING_NAMES",
+        "AutoModelForAudioFrameClassification",
+    ),
+    ("audio-xvector", "MODEL_FOR_AUDIO_XVECTOR_MAPPING_NAMES", "AutoModelForAudioXVector"),
 ]