Each of the supported types has a Canonicalize() method that generates a
JSON representation of the entry. If the golang library were to make a
change to the order of keys when marshalling an object, it would cause
a duplicate entry in the log for a semantically equivalent object.

This change simply transforms the JSON into RFC8785-compliant
canonicalized JSON protecting against any changes in JSON libraries
going forward.

Signed-off-by: Bob Callaway <bob.callaway@gmail.com>