unbox value class in Collection etc. when serializing

[k163377]

Fix for #464.

Currently, getter/field for value class returns unboxed content, but not if it is contained in a Collection or Array.
So I added a serializer to KotlinSerializers that unboxes the content (the details of the process are commented).
And also added tests for various situations.

About unbox processing of key.

I have not yet worked on the unbox handling of key in Map.
If there are no problems with this PR, I will try to address it in another PR.

Although ignored as a test case, serialization of value in Map has already been addressed as of this PR.

Known Issue

Currently, in Jackson, when multiple Serializer/Serializers are registered in ObjectMapper, the later registered Serializer seems to have priority.
Therefore, if a user registers a Module before a KotlinModule, the added ValueClassUnboxSerializer will have priority over the user-defined Serializer.

I was not able to solve this problem.
However, as far as I read Extentions.kt and so on, I think I can ignore this problem because KotlinModule is the first one to be registered in normal use cases.
Is there any problem with this policy?

Repletion

In the following comment, I wrote about my concern about the behavior when JsonValue is given, but it seems to be unfounded.
#464 (comment)

Jackson overrides the annotations given to classes or fields.
FasterXML/jackson-databind#586

[dinomite]

This makes sense to me. I'm reading through the test file to make sure I understand it (looks good and thorough at a glance), expect merging later today.

[dinomite]

I made a new issue (#469) for the map keys bit and updated that test to used expectFailure() rather than @Ignoreing the test (more on that: https://github.com/FasterXML/jackson-module-kotlin/blob/2.13/src/test/kotlin/com/fasterxml/jackson/module/kotlin/README.md).

[dinomite]

I added you to the credits as wrongwrong (k163377@github) and I'll be adding more entries for the prior PRs where I missed doing so (sorry!). Happy to use another name if you'd like.