Allow "production" of aliases to assist with naming style migration

[sschuberth]

As briefly discussed, here's a separate issue to track the feature request to allow the "production" of aliases, i.e. configure aliases globally similar to a PropertyNamingStrategy. Being able to do so would be great for backwards compatibility with existing JSON files when migrating from one naming style to the other.

Example: When changing serialization to use snake-style instead of camel-case, it would be great if deserialization would still accept camel-case to be able to read already written out files. Newly written files would only use snake-style, though.

[tyrantkhan]

would love this feature!