Add fusion commands to manage files in models space

[hbindu-ss]

This PR adds below fusion commands to upload/downloads LLM models from models space.

UPLOAD MODEL '<model_name>' FROM '<local_path>' [ OVERWRITE ];
DOWNLOAD MODEL '<model_name>'[ TO '<local_path>' ] [ OVERWRITE ];
DROP MODEL '<model_name>';
SHOW MODELS  [ AT '<path>' ] [ LIKE '<like>' ] [ ORDER BY '<order-by>' [ ASC | DESC ],... ] [ LIMIT ] [ RECURSIVE ] [ EXTENDED ];

cc: @ricardoasmarques @nunogoncalves03 @kanitsharma