Allow passing provider option to FastEmbed to allow embedding on the GPU

[alexkreidler]

Is your feature request related to a problem? Please describe.
I can't run the embedder on GPU so it is ridiculously slow

Describe the solution you'd like
Right now the DocumentEmbedder and TextEmbedder don't have the option to pass the provider for a model to the backend that creates the model:

haystack-core-integrations/integrations/fastembed/src/haystack_integrations/components/embedders/fastembed/embedding_backend/fastembed_backend.py

Lines 48 to 50 in 9db9ca1

	self.model = TextEmbedding(
	model_name=model_name, cache_dir=cache_dir, threads=threads, local_files_only=local_files_only
	)

This is the standard way to enable GPU support according to the FastEmbed docs:

embedding_model = TextEmbedding(
    model_name="BAAI/bge-small-en-v1.5", providers=["CUDAExecutionProvider"]
)

Seems like it would be a ~6 line change

[julian-risch]

@alexkreidler Thank you for the feature suggestion. Based on the fastembed documentation, my understanding is that this feature would require pip install fastembed-gpu. fastemebd-gpu cannot be installed in the same environment as fastembed.
I wonder whether a separate integration, fastembed-gpu-haystack, makes sense here because of the conflicting dependencies.
Would you use such a feature with a single GPU or multi-GPU? I am asking because for multi-GPU, we would want to expose more/other parameters based on this example from fastembed documentation.