feat: add (experimental) fine-tuning support with TRL (#9088)

* feat: add fine-tuning endpoint

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

* feat(experimental): add fine-tuning endpoint and TRL support

This changeset defines new GRPC signatues for Fine tuning backends, and
add TRL backend as initial fine-tuning engine. This implementation also
supports exporting to GGUF and automatically importing it to LocalAI
after fine-tuning.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

* commit TRL backend, stop by killing process

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

* move fine-tune to generic features

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

* add evals, reorder menu

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

* Fix tests

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

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Signed-off-by: Ettore Di Giacinto <mudler@localai.io>