Add Running Pace Zones (1 of 3)

.. in this first part we just add the pace.zones file
   and basic configuration of critical velocity history
   in the configuration pane.

.. in part 2 we need to fixup custom zones and consider
   how they might be adjusted for VDOT/Daniels etc etc

.. in part 3 we need to add pace zones to the ridefile
   cache and then histogram and summary charts.