Serialize more coders via URN + Class name

[kennknowles]

If the size of serializing Standard Coders becomes too large, an arbitrary Standard Coder can be encoded, alongside its components, via an URN and looking up the class when it is to be deserialized.

See tgroh@0708548 as an example

Imported from Jira BEAM-1939. Original Jira may contain additional context.
Reported by: tgroh.