Support java.time classes

[johnwright]

The types in java.time already have static parse methods:

• Instant
• OffsetDateTime
• ZonedDateTime
• LocalDate
• LocalTime
• LocalDateTime
• OffsetTime
• MonthDay

To reduce boilerplate, the static method lookup approach used in OptionalWrapper.Invoker could be refactored to support either class names (for runtime dependencies) or class objects. This could be an opportunity to generalise ReflectionValueParser, too.