Auto/Stealth Ride Import when opening an Athlete

...  import Ride Files automatically from a defined Directory per
Athlete
...  runs silently/without "Import Rides" Widget if the files can be
imported/copied/... without error or warning
...  Preferences->Athlete- defines
... the directory - per Athlete and- if the function is active at all
(default is OFF)
... the error handling
... report back ALL errors and warnings by opening the RideImportWizard
popup
... report back Errors and Warnings - but ignore the "File exists"
warning (so that the import directory can be continously supplied with
new files, without the need to remove the already imported ones)
Merge pull request #1094 from Joern-R/autoimport

Auto/Stealth Ride Import when opening an Athlete