Add AIStudio as a supported LLM library

[itsmvd]

This will make it easier for users to enable AI enabled features in Timesketch (just pull an API key from https://aistudio.google.com/), instead of having to export a GCP service account key.

This library also supports a response_schema, instructing/enforcing a response from a LLM model in a provided structure.

Example:

llm_provider = current_app.config.get("LLM_PROVIDER", "aistudio")
llm = manager.LLMManager.get_provider(llm_provider)(config=current_app.config.get("LLM_PROVIDERS",{}).get(llm_provider))

schema = {
    "type": "object",
    "properties": {
        "_id": {"type": "string"},
        "message": {"type": "string"}
    }
}
response = llm.generate("Give me the most suspicious event.", response_schema=schema)
print(response)

[jkppr]

LGTM