net: Move CConnman/NetEventsInterface after CNode in header file

Summary:

Can be reviewed with --color-moved=dimmed-zebra --patience

This is a move only change, no change in behavior.

Partial backport of core#20864:
https://github.com/bitcoin/bitcoin/pull/20864/commits/fa0a71781a964d944db9ecc002675ef32249f62e

Depends on D10879.

Ref T1696.

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Maniphest Tasks: T1696

Differential Revision: https://reviews.bitcoinabc.org/D10880