chore(model gallery): Add most of not yet present Piper voices from Hugging Face

[rampa3]

Description

This PR adds most of not yet in the gallery present Piper voices from the piper-voices Hugging Face repository (https://huggingface.co/rhasspy/piper-voices).

Left out models are:

• ar_JO models - while testing, models failed to load
• bg_BG-dimitar-medium - while testing, model failed to load
• de_DE-mls-medium - model output did not correspond to input, and seemed random
• fr_FR-mls-medium - model output did not correspond to input, and seemed random
• nl_NL-mls-medium - model output did not correspond to input, and seemed random
• uk_UA-ukrainian_tts-medium - produced only a single click as output
• vi_VN-vais1000-medium - model output did not correspond to input, and seemed random (language barrier?)

PR was created as reaction to issue #6083, "Add missing Piper voices".

This PR is one from a set of model additions I am working on currently, where I attempt to satisfy all not yet satisfied model requests I have found, which don't require any backend side changes (such as need for moderation endpoint for Qwen 3 Guard (requested on LocalAI Discord), or what would adding Mochi 1 (requested on LocalAI Discord) entail).

Notes for Reviewers

Models were tested for:

• correctly downloading and installing
• being correctly loaded by Piper backend
• speaking arbitrary test strings that all were able to reproduce in understandable way (letters "abc" and word "test")

Due to amount of added models, suppression of the model addition notification in LocalAI Discord might be needed to prevent spam if the PR is accepted.

Signed commits

• Yes, I signed my commits.

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[mudler]

Thanks!