Serializers for java.time.*

[aSemy]

https://github.com/Kotlin/kotlinx.serialization/issues/1806

What is your use-case and why do you need this feature?

We use a lot of java.time.OffsetDateTime which it is a bit cumbersome to have to annotate separately with a custom serializer like @Serializable(KOffsetDateTimeSerializer::class).

Describe the solution you'd like

It would be useful to have a special org.jetbrains.kotlinx:kotlinx-serialization-jvmtime dependency which automatically adds serializers to handle some very common classes from the java8 java.time module.

[Kantis]

I think it makes sense to start out with:

• [ ] Duration
• [x] Instant
• [x] LocalDate
• [x] LocalDateTime
• [x] LocalTime
• [x] OffsetDateTime
• [x] Year
• [x] YearMonth
• [ ] ZonedDateTime
• [ ] ZoneId
• [ ] ZoneOffset
• [ ] DayOfWeek
• [ ] Month

This means excluding these types for now:

• Period
• OffsetTime
• MonthDay
• Clock

Based on the assumption that these are less commonly used, especially in serial forms.

I think it's top priority to get support for:

• Instant
• LocalDate
• LocalDateTime
• YearMonth
• OffsetDateTime