[12780] Allow creating Non-Instance Maps without player
[12781] Move unused Map::LoadGrid function to function Map::ForceLoadGrid
[12782] Add new config setting LoadAllGridsOnMaps

With this setting one can store a list of maps that are automatically
loaded with all grids and all creatures.
Continents will be loaded on server-startup, instances when a player
enters.

NOTE: Using maps with this setting will cost huge amount of cpu and ram
power, and hence it must only be used for development purposes
[12783] Create function to load active entities.

Note this function is considered WIP, and will require further work pending more features

Ideas and loop to load all grids on a map by Neo2003.
[12784] Implement CREATURE_FLAG_EXTRA_ACTIVE

Setting this flag 0x1000 to creature_template.ExtraFlags will result in
the npc being loaded and set to active when the map is created.

In case of continents this will happen on server startup.

Note to DB-Devs: Use this flag with care, it will create more memory and
cpu usage for users.

Note to users: If you have a bottleneck and do not care about i.e. mobs
with huge paths, just remove this flag from the npcs