pass the lora dir into start req

[rusenask]

Enables the new sessions API to specify lora dir. Needs to be matching the lora dir within users account.

Example article https://www.theguardian.com/uk-news/2024/apr/13/squatters-york-albany-hotel-pub-gordon-ramsay-regents-park-london

Usage:

curl --request POST \
  --url http://localhost/api/v1/sessions/chat \
  --header 'Authorization: Bearer hl-ETHduXUj6-kzjUBNpXtkejxvU25m-R6ciuTxHnZqvEU=' \
  --header 'Content-Type: application/json' \
  --data '{
  "session_id": "", "lora_dir": "dev/users/d5680e7e-73a2-4a92-adc7-2d8d0c56b43a/sessions/c9b8d9b8-66e6-4537-9849-50d769c8e090/lora/8f223431-e2fe-40b6-a4f0-dceb0972f35d",
  "system": "You are an intelligent chatbot named Helix that has been fine-tuned on document(s) f3a0a7dd7d in document group c9b8d9b866.\nThe document group contains 1 document(s).\nThe user will ask you questions about these documents: you must ONLY answer with context from the documents listed. Do NOT refer to background knowledge.",
  "messages": [
    {
      "role": "user",
      "content": { "content_type": "text", "parts": ["who are living in this restaurant now?"] }
    }
  ]
}'
{"created":1713021064,"object":"chat.completion","id":"ses_01hvc05xtbmf58s2kc6wbjh8yz","model":"mistralai/Mistral-7B-Instruct-v0.1","choices":[{"index":0,"finish_reason":"stop","message":{"role":"assistant","content":"\n[DOC_ID:f3a0a7dd7d] [DOC_GROUP:c9b8d9b866]\n\nSquatters have taken over a pub in London leased by Gordon Ramsay. The group locked themselves inside the Grade II-listed York and Albany hotel and gastropub, next to Regent’s Park, boarding up the windows and putting up a notice defending their takeover. Ramsay called the police on Wednesday but was unable to have the people removed. The police consider it a civil matter. The property was previously owned by a film director and leased to Ramsay for 25 years. Ramsay tried to free himself from the lease in 2015 but failed. The venue went on sale at the end of last year with a guide price of £13m.\n "}}],"usage":{"prompt_tokens":0,"completion_tokens":0,"total_tokens":0}}