Various work on fields

[Tirlititi]

These changes mostly include backend work concerning fields:

• Introduce a couple of script API to change the ambiant light of fields (without the need to use custom binary files "MapConfigData").
• Improve readability of field collision code and the way it handles some specific objects in specific fields.
• There is a special event script function that triggers in vanilla when opening the menu, but only in the world maps. It is now possible to add such function in fields as well.
• Some changes in the field creator mode. It is still a work-in-progress. Also add an experimental shortcut Alt+F3 to reload the field's database on-the-fly.

Also, fix a visual bug in which the tab space was doubled in some situations for multi-choice dialogs, a bug that was introduced in #1502 when fixing a similar issue for dialogs in Japanese.