[Core or Module] Multiple items, quests, achievs required for access_requirement

[BarbzYHOOL]

This is a new feature, but most likely a refactor. I would like this to be a core feature.

Concept

Add new table for access_requirement (it's missing a "s"...) for items, quests and achievements.
This way, we can add multiple items requirements, multiple quests, and multiple achievements for a single dungeon/raid

table name: access_requirement_extra or mod_access_requirement_extra
structure: map_id | difficulty | requirement_type | requirement_data (or requirement_value
keys: unique key combination of all 4 rows (map_id, difficulty, requirement_type, requirement_data)

So we can now have multiple rows for the same map_id, examples:

455 | 0 | 0 | 458
455 | 0 | 0 | 459
455 | 0 | 0 | 460

map_id 455, will require the players to have 3 items in their bags (458,459,460).

requirement_type:
0 = item
1 = quest
2 = achievement

difficulty:
http://www.azerothcore.org/wiki/access_requirement