RTC: Implemented service interface.

Vancouver now tries to retrieve the current time in microseconds from
the rtc service, if possible.
RUN: Provide configuration for booting Linux VMs.

The setup now uses nitpicker and nit_fb to display several instances of
vancouver. The instances can be configured separately. The machine
config was extracted into an own file which has to be placed in the
build directory in order for the ISO image to be created
successfully.

Let launchpad pass Block, Nic, and Rtc.