[FEATURE] Localization strings

[Rainyan]

Description

We should probably use the engine's localization system for displaying text messages. This has a few advantages:

• The language data is decoupled from code into resource files, which (arguably) leads to cleaner code
• It's more accessible for non-programmer contributors to improve the language files
• Provides future support for different languages, if some were to be contributed, with minimal (if any?) code changes required

Proposed Solution

I have a WIP branch for this feature at: https://github.com/Rainyan/rebuild/tree/language - I'll post a PR once it's ready.

User stories:

• As a programmer, I don't want to spend too much time thinking up prose for user-facing interfaces.
• As a translator, I don't want to deal with programming code to improve the language files.

Alternatives Considered

The alternative would be to not do this. This would have marginal performance benefits, which would probably only make a meaningful difference in really hot paths, if any - in which case precaching such data should be an acceptable workaround.

Additional Context

No response