Deprecate the old PMC

.. its too far out of date;

   the UX is terrible and flickery
   its a cpu hog (deletes all objects on each replot !? wtf)
   it doesn't honour colour config
   it doesn't integrate with the sidebar date selection
   the metric selection should be via a reveal control
   can't hide the legend / set grid / use chart settings
   should use a tooltip
   doesn't work with compare

.. all these issues are resolved using an LTM based PMC

Fixes #880