Previously, for non-desktop configs, users could choose any number of
network management methods, including 0, 2, or more.
* gnu/installer/newt/services.scm (run-networking-cbt-page): Remove
'network-management?' parameter and select only 'networking services.
(run-network-management-page): New procedure.
(run-services-page): Call it when DESKTOP is the empty list.
* gnu/installer/services.scm (%system-services): Mark networking service
names with 'G_'.
* gnu/installer/newt/services.scm (run-networking-cbt-page): Pass
'system-service-name' through 'G_'.
* gnu/installer/newt/services.scm (run-networking-cbt-page): New procedure.
(run-services-page): Call it.
* gnu/installer/services.scm (%system-services): Add OpenSSH and Tor.
(networking-system-service?): New procedure.
* gnu/installer/steps.scm (format-configuration): Add 'networking' and
'ssh' to the service modules.
* gnu/installer/services.scm (<desktop-environment>): Rename to...
(<system-service>): ... this. Add a 'type' field.
(%desktop-environments): Rename to...
(%system-services): ... this.
(desktop-system-service?): New procedure.
(desktop-environments->configuration): Rename to...
(system-services->configuration): ... this. Determine the base list of
services based on whether SERVICES contains at least one "desktop"
service.
* gnu/installer/newt/services.scm (run-desktop-environments-cbt-page):
Adjust accordingly.
* gnu/installer.scm (installer-steps): Likewise.
Ludovic Courtès