Move some traits from RA.Buildings to Common
Move ShroudPalette, ShroudRenderer and StartGameNotification to Common

Move World into Traits folder
Move Burns from RA to Common, move RallyPoint to Traits folder
Move Valued, CustomSellValue and CustomBuildTimeValue to Common
Move Palette traits into Traits\World
Merge pull request #6921 from reaperrr/common-traits01

Moved various traits to Mods.Common