add E2EE functionality to nextcloudcmd

Thank you for developing Nextcloud and adding E2EE to the server.

In my setup / use case I desperately miss the E2EE compatibility of *nextcloudcmd* tool:
From various mobile devices I use the sync functionality to my server hosted by an external provider. I like to "client side" encrypt my data and this is working from the various GUI clients.

In a next step I would like to mirror the data from my external hosted server to my private lan based NAS. The NAS is headless so I'm using nextcloudcmd. However nextcloudcmd is not equipped with E2EE configuration parameters (as the GUI clients are).

Can you please add E2EE configuration parameters to nextcloudcmd (similar to parameters -u and -p)?

Thanks
Markus

### How to use GitHub

* Please use the 👍 [reaction](https://blog.github.com/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/) to show that you want to have the same feature implemented.
* Please don't comment if you have no relevant information to add. It's just extra noise for everyone subscribed to this issue.
* Subscribe to receive notifications on status change and new comments.

### Feature description
Tell us how the feature should work