gluon-config-mode: modularize wizard

This commit splits gluon-config-mode into several, mostly independent
packages.

* gluon-config-mode-core: basic functionality (required)
* gluon-config-mode-hostname: hostname field
* gluon-config-mode-autoupdater: show when autoupdater is enabled
* gluon-config-mode-mesh-vpn: fastd vpn configuration, bw limit
* gluon-config-mode-geo-location: geo coordinates
* gluon-config-mode-contact-info: contact info field

The package gluon-config-mode has been removed. You need to replace
it with these packages (or any subset of them) in site.mk:

* gluon-config-mode-hostname
* gluon-config-mode-autoupdater
* gluon-config-mode-mesh-vpn
* gluon-config-mode-geo-location
* gluon-config-mode-contact-info

Note: It is not possible to deactivate the autoupdater in config mode
anymore (expert mode will still allow it). Instead, a message is shown
in case the autoupdater is enabled.

package/gluon-luci-admin/Makefile

@@ -15,7 +15,7 @@ define Package/gluon-luci-admin
   SECTION:=gluon
   CATEGORY:=Gluon
   TITLE:=Luci based simple administration interface for mesh nodes
-  DEPENDS:=+gluon-luci-core +gluon-config-mode
+  DEPENDS:=+gluon-luci-core +gluon-config-mode-core
 endef
 
 define Package/gluon-luci-admin/description