Fix shelter and burning building starts

[LyleSY]

Summary

Bugfixes "Fix shelter and burning building starts"

Purpose of change

Fix #77474

Describe the solution

Adds a ZONE_START_POINT entry to each shelter variant
Removes ZONE_START_POINT from Road mapgen file

Describe alternatives you've considered

Reverting all #77451
Making big changes to #77451

Testing

Game loads no errors except an intermittent error on car crash. Sometimes that throws a tripoint mapgen error and lands you in the road outside a vehicle,

sometimes it puts you in a house.

Shelter start works:

Building on fire works:

Additional context

Should reopen #54731 until we can come up with a better fix

[PatrikLundell]

A question: Is "fix all of" picked up by the auto report closing logic, or should it be changed to "fix(ed)" for that to work?

[LyleSY]

Not sure! I've changed it just in case EDIT: Yes, had to use that language for it to kick in