LOITER waypoints distance not counted

When Mission Planner calculates mission distance it doesn't take into account distance of all loitering programmed in mission. All LOITER waypoints except LOITER_TIME and LOITER_UNLIM has explicit or implicit radius and number of turns and can be taken into account.

LOITER_TURNS distance can be calculated simply as D = 2_Pi_Radius*NumberofTurns
LOITER_TO_ALT distance can be estimated as D = (TargetAlt-PrevWPAlt)/tan(Pitch)

The issue names no files or tests. Start by locating Mission Planner's mission-distance calculation and its LOITER waypoint handling, then verify how LOITER_TURNS and LOITER_TO_ALT distances should be represented while excluding LOITER_TIME and LOITER_UNLIM. Done means applicable loitering distances are included and covered by tests.

Written by the indexing model from the issue text.