Move MapManager and related classes to Game SDK

[mudkipdev]

This class is duplicated heavily between games.

[emortaldev]

Note each game handles maps differently, not that it shouldn't be moved here.
E.g. ParkourTag loads all maps at start and then uses SharedInstances, Block Sumo creates all PolarLoaders at start and then creates new instances with that loader

[ZakShearman]

Thinking about this, different gamemodes have:

• Whether/not instances are shared or not
• Different dimensions
• Some have preloading, some don't. This could definitely be consistent.
• Different time rate and time update settings on the Instance
• Different 'map data' that is associated with each map and completely dynamic based on the gamemode.

I'm not saying no, it might be good to rework this but I'm not sure right now.