Lua: Add size and nationality optional parameters to edit.create_city()
City size change is coming in #44230, so it's possible to create cities of any size. What is missing from this ticket, is the ability to set the nationality of the very first citizen, created by edit.create_city().
Breaks old scripts that "pass" no_object (not even nil) as the fourth parameter.
Patch written from scratch. Adds new edit.city_create() and deprecates old edit.create_city()
We need it. Testing and more control of citizens' nationality may be added in another tickets but it's a base. At very least city size should be configurable by Lua. I added some improvement to create_city() code during #44312 but that actually has not been tested yet (with e.g. city_size > 1 units).