add couchbaseJsonValueModule bean to AbstractCouchbaseConfiguration

[mikereiche]

https://forums.couchbase.com/t/setting-json-deserialisation-features-in-java-sdk-3/30215/6

We Could change contentAsObject() to always use JacksonTransformers.bytesToJsonObject() so it doesn't depend on the user registering the correct module. What do you think?
Should also add another preflight check and fail if JsonValueModule isn't registered.

[mikereiche]

This is a "feature" but I've marked it as a bug a as it really should have been like that in the first place.