Move to tinyaes for cryptography stuff

We are currently using PyCryptodomex, which works perfectly fine.

But it is a quite big dependency (14 MiB) for our needs (AES encryption).
When the tinyaes module will be made available on GNU/Linux, macOS and Windows, we could give it a try (waiting on https://github.com/naufraghi/tinyaes-py/pull/8 [OK]).

This become particularly important since when the application needs to be notarized on macOS, and smaller final package would be appreciated (less network consumption, less time to upload the file and less time for Apple servers to do their work). And as a generale rule, smaller installers would be a good thing.