Add CM support for private configuration for rclone

[gfursin]

We had to remove configs with private keys from the CM get-rclone script.

We need to add proper support to handle such private keys. We can use the new CM cfg automation or create a "get-rclone-config" script.

TBD: should brainstorm more.

[gfursin]

Hi @arjunsuresh . I didn't manage to merge private key for get-rclone for MLCommons datasets (even though it seems to be "public") - GitHub refused a commit. We should either find a workaround to push it back or create a script to register them locally without pushing to Git ...