Port Fairseq TTS models (#2628)

* Load fairseq models

* Add docs and missing files

* Managing fairseq models and docs for API

* Make style

* Use scarf URL

* Add tests

* Fix URL

* Pass cpu

* Make lint

* Fixup

* Make lint

* fixup

* Fixup

* Change tokenization order

* Update README

* Fixup

* Fixup

tests/inference_tests/test_python_api.py

@@ -60,7 +60,7 @@ if is_coqui_available:
             self.assertIsNone(tts.languages)
 
         def test_studio_model(self):
-            tts = TTS(model_name="coqui_studio/en/Torcull Diarmuid/coqui_studio")
+            tts = TTS(model_name="coqui_studio/en/Zacharie Aimilios/coqui_studio")
             tts.tts_to_file(text="This is a test.")
 
             # check speed > 2.0 raises error
@@ -83,6 +83,10 @@ if is_coqui_available:
             wav = tts.tts(text="This is a test.", speed=2.0, emotion="Sad")
             self.assertGreater(len(wav), 0)
 
+        def test_fairseq_model(self):  # pylint: disable=no-self-use
+            tts = TTS(model_name="tts_models/eng/fairseq/vits")
+            tts.tts_to_file(text="This is a test.")
+
         def test_multi_speaker_multi_lingual_model(self):
             tts = TTS()
             tts.load_tts_model_by_name(tts.models[0])  # YourTTS