Further develop "LoadAllGridsOnMaps" and add preset options

Previous entry on this issue: https://www.getmangos.eu/bug-tracker/mangos-zero/archived-reports/Discuss-adding-options-for-wor-r316/

So I have been running the Covenant-WoW servers now for a few months with the living world enabled on both Classic and TBC.

Issues identified: To much CPU usage and to much RAM usage.

Suggested additions needed to "LoadAllGridsOnMaps"

1. Add some presets:
   1. Load all city grids
      • Keeps all city NPCs loaded in every city at all times.
   2. Load all sanctuary's
      • Keeps any city marked as a Sanctuary loaded at all times.
   3. Load all towns
      • Keeps all towns loaded at all times.
   4. Load all NPCs with pathing (waypoints) set, in world maps (0,1,530) and so on.
2. Add ability to load individual grids along aide maps "LoadGrids" option.
3. Load grids based on player position
   1. Loads grids within 2 grids of a player.
4. Add NPC override option in the database
   1. Give an NPC the ability to load regardless of the grids status it is on. This would force the grid to load and be treated as a "LoadGrids".

If we get to a point with transports working with NPCs I would like to see transports exempt from the grid setting and always loaded. They have so little NPCs on them they should always be loaded regardless of anything else. //discuss