Add support for platform specific localized display names for DayOfWeek and Month

[adrcotfas]

Hello there,

Some context:

• I'm migrating a project from Android Compose to Compose Multiplatform
• On Android I was using java.time.Month.getDisplayName and java.time.DayOfWeek.getDisplayName and I miss that functionality
• I've added some logic here to retrieve the localized names on jvm and darwin targets using a Locale and a java.time.format.TextStyle inspired TextStyle.

I've added DayOfWeekNames.ENGLISH_NARROW and MonthNames.ENGLISH_NARROW to use together with the ENGLISH_FULL and ENGLISH_ABBREVIATED as fallback for displayName.
These were defined as List<String> because could contain duplicate entries, to not accidentally pass them to the DateTimeFormatBuilder which currently expects different entries for day/month names.

I'm looking forward to your feedback and in the meantime I'll be using this: https://github.com/adrcotfas/kotlinx-datetime-names (there's a demo there).