Vehicle position -> absolute

[PatrikLundell]

Summary

None

Purpose of change

Convert code to keep track of which map it operates on rather than (almost) always assume it's the reality bubble.
This time the focus was on changing the vehicle position to absolute rather than bubble coordinates relative to some undefined map (typically a local mapgen one or the reality bubble). Code sort of happened to work for some reason when mapgen maps were used to generate bubble ones.

Describe the solution

Convert a few vehicle operations, but mainly change the vehicle position data.

Describe alternatives you've considered

Spend additional effort trying to work around the need for map references. That was possible in a few cases (getting the absolute position, which gets what's stored, and thus doesn't need any map reference, to feed an operation that can take either an absolute or a bubble coordinate, such as getting a monster at a location). Thus far only easy cases have been spotted.

Testing

Running tests locally (a number of errors were shown before being found, including the one stumping me on an earlier attempt).
Play testing, i.e. a couple of hours of normal game play with a lot of driving around (and thus generation of vehicles on new maps) without seeing anything odd.

Additional context