build/vagrant: delete broken Vagrant configuration file

According to Tobias, this file is broken because I moved it from the
top-level directory to the build/ folder.  Since nobody seems to be
willing to fix it, I hereby delete it, to avoid confusion.
FlarmId: make UNDEFINED_VALUE a constexpr variable
RowFormWidget: add "vertical" layout
Dialogs/TrafficList: implement lookup filter

Everts the dialog: instead of showing the keyboard first and then the
list with matches, the dialog now shows an empty list and then allows
the user to manipulate the filter incrementally.  More filter options
to come (and SkyLines traffic).
FLARM/Friends: move enum Color to FlarmColor
Flarm/Friends: move code to class FlarmColorDatabase

Prepare for exposing internals to allow iterating the database.
Trace: increment modify_serial after time warp recovery

Fixes an assertion failure in SyncPoints(), called by
ContestDijkstra::UpdateTraceTail().
FlarmDetails: move code to class FlarmNameDatabase
FlarmDatabase: rename to FlarmNetDatabase
FlarmFriends: move code to FlarmProfile.cpp
FlarmDetails: move code to NameFile.cpp
test/TestFlarmNet: use FlarmNetDatabase

Use the low-level API instead of the FlarmNet namespace.
FLARM: merge all database instances to TrafficDatabases

Use one global variable that has everything instead of one global
variable per subsystem.
BigTrafficWidget: use FLARM/FriendsGlue.hpp

Eliminate duplicate code for assigning the team color.
TeamCode: add method IsDefined()

Eliminates TeamCodeSettings::team_code_valid and
TeamInfo::flarm_teammate_code_available.
TeamCodeSettings: remove attribute team_flarm_tracking

Use team_flarm_id.IsDefined() instead.
test/TestTeamCode: new unit test
TeamCode: optimise GetBearing() and ConvertBearingToTeamCode()

Use a "constexpr" factor and native angle encoding instead of going
the roundtrip through degrees.
TeamCode: use unsigned integers
TeamCode: add constant "BASE"

Derive TEAMCODE_COMBINATIONS and others from it.  This is more clear.