docs/features/wired-mesh: update to role-based configuration (#2584)

- explain what happens on gluon-reconfigure
- show workflow to alter the wired network config
- update examples
- update 'has changed in' section

resolves #2474

Co-authored-by: Tom Herbers <mail@tomherbers.de>
Co-authored-by: David Bauer <mail@david-bauer.net>
Co-authored-by: Andreas Ziegler <dev@andreas-ziegler.de>

Co-authored-by: Tom Herbers <mail@tomherbers.de>
Co-authored-by: David Bauer <mail@david-bauer.net>
Co-authored-by: Andreas Ziegler <dev@andreas-ziegler.de>