[RFC 322] Implemented copy/Copyable deprecation

[lupestro]

At long last, I finally delivered an implementation of the RFC. Sorry for the delay.

• Take a close look at the substitution of a shallow copy for a deep one on the three affected tests in decoupled_basic_test. If we have to do a deep copy for the test to be valid, I'll have to research what's needed.
• I explicitly made copy private - hopefully that's okay. Copyable had always been private.

[rwjblue]

Looks good to me! I’m going to land this and we can work on the svelting stuff in a follow up...

[rwjblue]

Thank you!