MEGA.nz support

[federicotorrielli]

Please agree to the following

• [X] I have searched existing issues for duplicates
• [X] I agree to follow this project's Code of Conduct

Summary

Add support for MEGA.nz

Motivation

Adding this here following the previous issue here, just to track things.

Considered Alternatives

No response

Anything else?

We could use the MEGA sdk, here.

[tobihagemann]

Depends on https://github.com/cryptomator/cloud-access-swift/issues/11