feat: add mistral as a new guardrail provider

[b4s36t4]

Title:

• Mistral Moderations support for guardrail plugins.

Related Issues: (optional)

• /closes [Feature] Add Mistral Moderations API as a guardrail Provider #755

[b4s36t4]

Example curl Request:

curl --request POST \
  --url http://localhost:8787/v1/chat/completions \
  --header 'authorization: <api_key>' \
  --header 'content-type: application/json' \
  --header 'x-portkey-config: {"before_request_hooks": [ {"type":"guardrail", "name": "test", "checks": [ {"id": "mistral.pii", "parameters": { "credentials": {"apiKey":"<mistral_api_key>" }}} ]} ]}' \
  --header 'x-portkey-provider: groq' \
  --data '{
  "messages": [
    {
      "role": "user",
      "content": "Say Hi. My name is Jhon Doe and my email is user@example.com"
    }
  ]
}'

Supported guardrails are

'sexual', 'hate_and_discrimination', 'violence_and_threats', 'dangerous_and_criminal_content', 'selfharm', 'health', 'financial', 'law', 'pii',