Extract expected travel durations from Garmin BaseCamp GDB output (#585)

Extract expected travel durations from Garmin BaseCamp GDB output (#585)

* extract track segment expected travel durations from Garmin BaseCamp autorouted GDB exports and report as <rtept/src> elements in gpx output

* revised to use Garmin Format-Specific Data object to store durations

* generate at frozen test time

* include code review suggestions

* store Garmin BaseCamp autoroute waypoint travel durations in the <desc> elements of <rtept> waypoints; modify gpx ouptut to exclude autoroute generated rtept waypoints from initial waypoint list

* remove waypoint class lookup and replace tabs with spaces

* run astyle on gdb.cc

* turn off detailed GDB debugging

Co-authored-by: tsteven4 <13596209+tsteven4@users.noreply.github.com>