Since knowledge of CAddrInfo is limited to callsites that import
addrman_impl.h, only objects in addrman.cpp or the tests have access. Thus we
can remove calling them friends and make the members public.
Now that no bitcoind callers require knowledge of the CAddrInfo object, it can
be moved into the test-only header file.
Review hint: use git diff --color-moved=dimmed-zebra
--color-moved-ws=ignore-all-space
CAddrInfo objects are an implementation detail of how AddrMan manages and adds
metadata to different records. Encapsulate this logic by updating Select &
SelectTriedCollision to return the additional info that the callers need.
Introduce the pimpl pattern for CAddrMan to separate the implementation details
from the externally used object representation. This reduces compile-time
dependencies and conceptually clarifies AddrMan's interface from the
implementation specifics.
Since the unit & fuzz tests currently rely on accessing CAddrMan internals, this
commit introduces addrman_impl.h, which is exclusively imported by addrman.cpp
and test files.
Review hint: git diff --color-moved=dimmed-zebra
--color-moved-ws=ignore-all-space
