Implement tor_memquota:HasMemory cost for a lot of types

We'll need this to track the data in queues.

This is basically:

• Introduce a derive macro
• Apply it to lots and lots of things

I've chosen to make the dependencies from tor-units tor-llcrypto tor-hscrypto conditional, but not above that. (tor-proto is going to need this unconditionally anyway.)

This is probably not all the required HasMemoryCost impls, but it's most of the ones I've discovered so far that I need.

Part of #351 (closed)