Custom stop sequences in settings

[manyoso]

• some models output the wrong EOS token, so this is important
• special tokens show up as blank in output because we use llama_token_to_piece with special=False, so they aren't even considered for our current hardcoded reverse prompts

Related things to fix:

• Don't loop forever when the model generates a special token other than EOS (https://github.com/nomic-ai/gpt4all/issues/2167)
• Print special token content
• Honor both EOS tokens specified in the HF model's generation_config.json (requires llama.cpp modification)

[ThiloteE]

refs https://github.com/huggingface/transformers/pull/28932 refs https://github.com/ggerganov/llama.cpp/issues/5040

I cannot seem to find the issue/pr that talks about multiple eos in llama.cpp.

[manyoso]

Duplicate of https://github.com/nomic-ai/gpt4all/issues/2439