Previously, JacksonAutoConfiguration would register any Jackson Module
beans with every ObjectMapper found in the application context. This
was not consistent with the rest of the Jackson auto-configuration,
which is only applied to ObjectMappers that are created or configured
via the auto-configured Jackson2ObjectMapperBuilder.

This commit removes the code that registers Jackson Module beans with
every ObjectMapper. Such beans will still be registered with
ObjectMappers created or configured using the auto-configured
Jackson2ObjectMapperBuilder. This aligns the configuration of Module
with the rest of the ObjectMapper configuration and makes it possible
for users to create an ObjectMapper bean and still have complete control
over the modules that are registered with it.

Closes gh-2489