fully support share links as an additional / alternative option to full account login for r/w access to files/folders.

Instead of requiring a full proton account login it should be possible to use as share link (password protected or otherwise) to access nodes via the cli.

This would greatly simplify using the CLI or SDK in headless setups and other tools like rclone and also vastly reduce the threat model in case of compromised keyring, fault in credential handling in the CLI etc.