New Metrics for MTB - Bike Carrying Time/Elevation Gain

... 2 new metrics (estimates) mainly relevant for MTB or Race bike steep
passes
... a) Time Carrying = moving < 8kph, gaining height, no power, no
cadence
... b) Elevation Gain carring = same criteria, but adding up the
elevation gain

Since there is a certain level of error, the metrics is named as "Est".
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Fix UUID for Season

.. must be unique as used to select even when
   name is changed or translated.

.. Thanks to Claus Assmann for the fix.
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of https://github.com/GoldenCheetah/GoldenCheetah
Merge branch 'master' of https://github.com/Joern-R/GoldenCheetah