[dynamodb] Fixed persistence issues with zoneddatetime (#9157)

[dynamodb] Fixed persistence issues with zoneddatetime (#9157)

* [dynamodb] fix serialization of ZonedDateTime timestamps

Resolves #9156.

AWS SDK does not know how to serialize ZonedDateTime. We resolve this
by providing explicit serializer/deserializer.

In addition, integration tests had issue with timezones. The persistence
converts all timestamps from the DynamoDB to system timezone for display
purposes. This was not taken into account in the tests and failure was
expected with non-UTC system timezone.

Signed-off-by: Sami Salonen <ssalonen@gmail.com>