feat!: cleanup and complete removal of ether.js

[chybisov]

[mathiasmoeller]

When this is ready, before we release it, we should also try to integrate it in the BE and see how that goes :)

[mathiasmoeller]

This PR introduces so many changes that it's hard to track what we need to do in the backend.
To break it down I started this change here which is minimal and now I'm integrating that in the backend
https://github.com/lifinance/types/compare/tx-request?expand=1