Cache the initial path layer for faster path search startups.

Reinitializing the initial cell info layer for the path search took a fair bit of time. We cache this initial setup so it only has to be done each time the map size changes. A CopyValuesFrom method in CellLayer is provided which copies values between layers by just copying the internal arrays for super speed.

This speeds up InitCellInfo 10x.
Move more files

Move VoxelNormalsPalette to TS
Merge pull request #7122 from penev92/bleed_moveFiles

Move more files away from OpenRA.Mods.RA
Merge pull request #7108 from RoosterDragon/faster-path-init

Cache the initial path layer for faster path search startups.
Move more traits from Mods.RA to Mods.Common
Rename Util.cs to BuildingUtils.cs
Move Activities CallFunc, RemoveSelf and SimpleTeleport to Common
Move various RA-specific traits to the new folder/namespace structure
Move 'Activity' into its own namespace in OpenRA.Game.