init: set pkgpriorities

The infamous systemd infiltration through secondary
"targets" using virtual dependencies started with
syslogd-daemon, continued with network-config-subsystem
and later with ntp-server; all of its implementations
pulling in the main package which is explicitly unwanted
in sysv-based images.

Let's try employing pkgpriorities.

features.in/init/config.mk

@@ -1,9 +1,11 @@
 +sysvinit: use/init/sysv; @:
 +systemd: use/init/systemd/full; @:
 
-use/init:
+# NB: the list name MUST be identical to init package name
+use/init: use/pkgpriorities
 	@$(call add_feature)
 	@$(call add,THE_LISTS,$$(INIT_TYPE))
+	@$(call add,PINNED_PACKAGES,$$(INIT_TYPE))
 
 # THE_LISTS is too late when BASE_PACKAGES have pulled in
 # the wrong syslogd-daemon provider already