[feature] Add i18n API for Multilingual Support in Endstone

[wu-vincent]

Is your feature request related to a problem? Please describe.
Currently, there’s no API in Endstone for handling multilingual messages.

Describe the solution you'd like

1. Introduce Endstone's language files for translation.
2. Use BDS language file as a fallback if the key does not start with endstone..
3. Translatable messages should be sent as-is to the client, allowing resource packs to handle their own translations, except for keys starting with endstone. which should be translated server-side.
4. Allow retrieval of translated messages using server.getLanguage().translate(key, params).

Describe alternatives you've considered
N/A

Additional context
This API would follow a design similar to PocketMine-MP and Nukkit.

[smartcmd]

👀

[github-actions]

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