* gnu/services/networking.scm (maybe-number?, maybe-string?): New procedures.
(<opendht-configuration>): New configuration record.
(%opendht-accounts): New variable.
(opendht-configuration->command-line-arguments): New procedure.
(opendht-shepherd-service, opendht-service-type): New variables.
* doc/guix.texi (Networking Services): Document the new service.
