RVC model merging and conversion

[bobcate]

I have 3 feature requests:

1. RVC model merging
2. RVC model conversion between all available formats (.pth | .onnx | .safetensors | ...(?))
3. Usage support for all RVC model formats

Relevant:
RVC WebUI and Applio has a model merger(aka fusion/blender).
w-okada has a button to convert .pth to .onnx, and has a model merger.
A w-okada fork automatically converts .pth to .safetensors upon upload, and has a model merger.
These scripts supposedly convert models but I couldn't get them to work.

great work with the V2 btw