Custom serialization logic for u64
Custom serialization logic for u64

We were running into issues where u64 values were serializing as JSON
strings and not making it back to u64 when they deserialized. Not
quite sure how this isn't being handled automatically by Rust's type
system, but in any event, we can just plug in our own logic with some
attributes.

Signed-off-by: Christopher Maier <b4598f17a90ef80817bae8ad6c37249740caafb4@chef.io>

habitat-sh/habitat,nathenharvey/habitat,habitat-sh/habitat,georgemarshall/habitat,georgemarshall/habitat,habitat-sh/habitat,georgemarshall/habitat,rsertelon/habitat,habitat-sh/habitat,nathenharvey/habitat,habitat-sh/habitat,rsertelon/habitat,georgemarshall/habitat,georgemarshall/habitat,rsertelon/habitat,rsertelon/habitat,nathenharvey/habitat,georgemarshall/habitat,nathenharvey/habitat,nathenharvey/habitat,habitat-sh/habitat,rsertelon/habitat,rsertelon/habitat,georgemarshall/habitat,rsertelon/habitat,habitat-sh/habitat,habitat-sh/habitat,nathenharvey/habitat,georgemarshall/habitat