generate safe tls plans

[behrisch]

netconvert should insert an all red phase if the length of the yellow phase is longer than max speed divided by length for each link. If there is already an all red phase configured it should be made longer by the given calculated amount (crossing time minus yellow time). furthermore to calculate crossing time we need to calculate the time needed to cross the whole junction at full speed but also the time to get from being stopped at an internal junction to the "exit".

[behrisch]

The crossing time for the whole junction is respected now but only for connections which start with an edge allowing passenger cars (due to #10976). The part which checks whether the vehicle can accelerate from the inner junction in time is still missing.