Ridecace Measures deprecated from SQLite

This is quite a big patch with lots of nasty interdependencies
all collected together but essentially it deprecates;

* Measures are no longer stored in SQL tables
* Zeo support has been dropped (they went bust)

To achieve this there are a large number of updates;

* Withings json is now cached in /cache and in the Athlete
  class. So can be traversed in memory rather than SQL

* All "measures" on LTM have been removed and the only metric
  left is "Athlete Weight" that cascades from withings to ride
  "Weight" metadata value to athlete settings to a 80kg default

* RideCache is now refreshed, but only for metadata. This is needed
  to cache the "Weight" metadata from rides when calculating weight.

* JsonRideFile parser is now re-entrant since it will run in parallel
  during RideCache refreshes (using the QtConcurrent::map()
  framework).

BUT NOTE

* This is about deprecating the Measures table more than anything
  else. Functionally we are in pretty much the same place; just that
  data is stored in a different place.

  e.g. metric/imperial handling of weight is not fixed yet, no
  metrics are in the cache yet, load/save of the cache is not done
  so startup is slow etc.