feat: raw phonemes

[thewh1teagle]

Add option to pass raw phonemes to piper
This is useful when using custom phonemizers

wget.exe https://huggingface.co/rhasspy/piper-voices/resolve/main/en/en_US/bryce/medium/en_US-bryce-medium.onnx
wget.exe https://huggingface.co/rhasspy/piper-voices/resolve/main/en/en_US/bryce/medium/en_US-bryce-medium.onnx.json
# set `"phoneme_type": "raw"` in `en_US-bryce-medium.onnx.json`
cmake -B build .
cmake --build build
echo "həlˈəʊ fɹɒm pˈaɪpə" | ./build/piper -m en_US-bryce-medium.onnx -c en_US-bryce-medium.onnx.json -f audio.wav
ffplay audio.wav # hello from piper

Also I added the option to preprocess metadata.csv where instead of text we can have phonemes (when using custom phonemizer). in the preprocess it takes them as is, and skip the phonemization.

[morrisalp]

Bumping this, this is a very important feature for my use case (training and inference on new language directly using IPA).

[synesthesiam]

Development has moved: https://github.com/OHF-Voice/piper1-gpl
I think the "text" phonemes type should behave similar to how you have "raw" here, no?