Add language selector to settings

[wjt]

It is common in games (unlike productivity applications etc.) to be able to override the language of the game, rather than following the system language.

Add a new section to the settings page where the game language can be chosen. It should include all supported languages (currently English & Spanish, but these should be found with some Godot API to list available translations rather than by hardcoding the list!) plus an option to "Use System Language". English should always be shown as "English" and Spanish should always be shown as "Español", regardless of what language the game is in. "Use System Language" should be translated.

This setting should be saved in the same place as the other settings in res://scenes/globals/settings/settings.gd. (There are currently two files used by that module; the person implementing this task should determine whether user://settings.cfg, or user://custom_overrides.cfg, is the better location.)

The list of languages should not use flags to represent languages. Spanish is spoken in many countries; and many languages are spoken in the USA.

XP Summary (total 525)

Subdomain	Skill	XP
Engineering: Gameplay & Systems Programming	Problem Solving	75
Engineering: Gameplay & Systems Programming	Creativity & Design Thinking	75
Engineering: Gameplay & Systems Programming	Technical Literacy	150
Game Design: Game Feel & UX	Problem Solving	75
Game Design: Game Feel & UX	Creativity & Design Thinking	75
Game Design: Game Feel & UX	Technical Literacy	75

[manuq]

Reopening because I did #2104 without considering this issue:

• The English/Spanish are hardcoded. Initially I tried a dropdown menu, but it looks very bad because we don't have theme for it.
• It defaults to the system language, but I haven't considered adding a "Use System Language" to revert it. Is a great idea.