Add i18n to epic stack

I think internationalization is common nowadays, and most projects should start with it since implementing it in mature projects is costly.

In [this discussion](https://github.com/epicweb-dev/epic-stack/discussions/44), it is said that i18n is planned, but it is still not implemented. There is [this example](https://github.com/rperon/epic-stack-with-i18n/) project that can be migrated to this project.