2a07f878a Refactor: Modernize disallowed copy constructors/assignment (Dan Raviv)
Pull request description:
Use C++11's better capability of expressing an interface of a non-copyable class by publicly deleting its copy ctor and assignment operator instead of just declaring them private.
Tree-SHA512: 878f446be5a136bb2a90643aaeaca62948b575e6ef71ccc5b4b8f373e66f36ced00665128f36504e0ccfee639863d969329c4276154ef9f2a9de9137f0801e01
Backport of Core PR11351
https://github.com/bitcoin/bitcoin/pull/11351