Refactor: moved model, attentions definitions and inference code to style_bert_vits2/models/

The code has not yet been cleaned up, just moved.

app.py

@@ -26,7 +26,7 @@ from style_bert_vits2.constants import (
 )
 from style_bert_vits2.logging import logger
 from common.tts_model import ModelHolder
-from infer import InvalidToneError
+from style_bert_vits2.models.infer import InvalidToneError
 from style_bert_vits2.text_processing.japanese.g2p_utils import g2kata_tone, kata_tone2phone_tone
 from style_bert_vits2.text_processing.japanese.normalizer import normalize_text