move-only: Group and re-order CAddrMan members by access type

Summary:
Order them as public:, protected:, private:. There is no change, move only.

Completes backport of core#22025:
https://github.com/bitcoin/bitcoin/pull/22025/commits/8caf60dbbe16afa3c52574a7f6710d74c0bfd4ab

Depends on D12253.

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D12254