Duration support

[kkurczewski]

Issue: https://github.com/FasterXML/jackson-module-kotlin/issues/683

Adds converter and deserializer which bridges conversions between kotlin.time.Duration and java.time.Duration.

In order to properly deserialize data class with duration following hacks are needed:

• class need to have explicit static factory annotated with @JsonCreator, primary ctor won't cut it
• in data class definition value-class getter has to be annotated with Duration converter

Notes:

• later Kotlin version adds dedicated method kotlin.time.Duration.toJavaDuration() which can be used instead ISO parsing (in converter)
• ...and adds dedicated extension method java.time.Duration.toKotlinDuration() which can be used instead ISO parsing (in deserializer)

[k163377]

Sorry, but it seemed better to add a KotlinFeature as you originally suggested. It seems counter-intuitive to have an error message saying that the JavaTime module is required when processing Kotlin Duration.

[cowtowncoder]

CLA received.

[kkurczewski]

Rebased (other Kotlin feature added which cause conflict)

[k163377]

As for the code, it is LGTM, thanks for the contribution!