Degraded mode for vehicle tracking when missing MetricOffset (corrupted data)

Commit 0c3bd0d5 is a temporary workaround which forbids to use paths with missing MetricOffset on edges instead of having hundreds of rejections due to corrupted data.

Now we want the algo to evaluate/calculate the MetricOffset when they are missing so the tracking could work (with some probable imprecision).

There is 2 possibilities for calculate the missing values:

• Use the last GPS projection
• Project the stop point on the road

Obviously these values should be computed only once at the beginning of the travel