net: avoid NM showstopper at boot by default

Intro: NetworkManager-wait-online.service would, well, wait
for some network interface to become online or for timeout
to kick in.

Problem: if a LiveCD is tested in offline environment
that timeout will only impede the boot.

Proposed solution: use/net/nm/nodelay target has been implemented
to disable that service as proposed by sem@ and done in Simply;
"+nm" target changed to be an alias to this one.

features.in/net/config.mk

@@ -1,4 +1,4 @@
-+nm: use/net/nm; @:
++nm: use/net/nm/nodelay; @:
 
 use/net: use/services
 	@$(call add_feature)
@@ -12,6 +12,9 @@ use/net/nm: use/net
 	@$(call add,THE_LISTS,$(call tags,desktop nm))
 	@$(call add,DEFAULT_SERVICES_ENABLE,NetworkManager ModemManager)
 
+use/net/nm/nodelay: use/net/nm
+	@$(call add,DEFAULT_SERVICES_DISABLE,NetworkManager-wait-online)
+
 use/net/connman: use/net
 	@$(call add,THE_PACKAGES,connman)
 	@$(call add,DEFAULT_SERVICES_ENABLE,connman)