feat: Download model directly from HF url

[namchuai]

Problem
Download model directly from Hugging face url

Success Criteria
Model is able to download and can be used after download successfully

Additional context
#1004 (comment)
#1077

[gabrielle-ong]

QA:
Without Variants -> triggers variant selection

1. cortex pull eg tinyllama → from cortexso HF
2. cortex pull <HF repo_id/model_id> eg TheBloke/Mistral-7B-Instruct-v0.1-GGUF

With variants
3. cortex pull egtinyllama:gguf-> from cortexso HF 4. cortex models pull <HF URL> eghttps://huggingface.co/BafS/gemma-2-2b-it-Q4_K_M-GGUF/blob/main/gemma-2-2b-it-q4_k_m.gguf`

✅ Mac
✅ Windows
✅ Linux