base-files, systemd: add nss-resolve plugin

base-files, systemd: add nss-resolve plugin

Add nss-resolve plugin to the glibc Name Service Switch (NSS) with
systemd-resolved DISTRO_FEATURE so that systemd-resolved is used in DNS
name resolution.

This enables the resolution of Multicast DNS and Link-Local Multicast
Name Resolution names, depending on the selected options.

Signed-off-by: Eero Aaltonen <eero.aaltonen@vaisala.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>