* add opencpop voc, test=tts

* soft link

* add opencpop hifigan, test=tts

* update

soft link for shell in example, add skip_copy_wave in norm stage of GANVocoders to save disk

move link_wav.py to paddlespeech/t2s/exps/gan_vocoder/ so that different vocoders can use one script.

add --dataset and --rootdir to voc3 finetune script, also remove --speaker-dict in voc5.

* add hifigan

* add hifigan

* integrate synthesize synthesize_e2e, inference for tts, test=tts

* add some python files, test=tts

* update readme, test=doc_fix