Replace the current internationalization and localization (i18n and l10n) structure

[remyroy]

The current i18n and l10n structure in this project uses customs paths, files, functions and methods to adapt the application to different languages, regional peculiarities. We should move it to a structure and tooling that is more standard and easier to work with.

This is likely going to be a long-term goal with some good efforts.

Part of this should also make it easier for anyone to contribute to the internationalization and localization of this project.

This was part of the discussion we had with Trail of Bits during their presentation of the EthStaker Deposit CLI Security Assessment DRAFT report on October 8 2024.

Potential tools for this include the gettext standard library.

Related to #184 .