Support configuring interface language per user (#1406)

## Description
Adds a setting to configure the app's language/locale. It is configured
per user. This settings has no impact on audio or subtitles language
choices.

Only languages Wholphin has translations for can be used. If you would
like to contribute new translations, check out
https://translate.codeberg.org/projects/wholphin/!

Dev notes: This doesn't exactly follow Android's recommendations because
the [guidelines are for
per-app](https://developer.android.com/guide/topics/resources/app-languages)
and not users within the app.

### Related issues
Closes #513
Closes #669

### Testing
- Emulator API 34
- Nvidia shield API 30
- Fire TV OS 7 API 28

## Screenshots
<img width="1280" height="720" alt="language Large"
src="https://github.com/user-attachments/assets/bf1c0962-8a36-4012-aed9-eab564fc1114"
/>

## AI or LLM usage
None

app/build.gradle.kts

@@ -184,6 +184,9 @@ configure<ApplicationExtension> {
     lint {
         disable.add("MissingTranslation")
     }
+    androidResources {
+        generateLocaleConfig = true
+    }
 }
 
 androidComponents {