setup-interfaces: call ifup -a (or rc-service networking restart?)

It seems something like ifup -a is currently (only) called by setup-alpine to enable the network, but not when calling setup-interfaces directly.

Edited:

NB: Looks like the network may onlyalso be started with setup-ntp, as a side-effect ("need net") of the ntpd and chrony service dependencies.

But generally, the network should probably also be (re)started as part of setup-interfaces, setup-dns and others that depend on it (if not called from setup-alpine to avoid repeated restarts), to make them functional in itself.

Allowing them to be effective for modifying an alpine system, and to allow them to prepare the system for the user to be able to install packages and make adjustments, before running setup-alpine.