also measure render performance bottle necks

closes #4133
Add System.Core reference to OpenRA.Mods.Common.csproj for Linq
Merge pull request #6876 from Mailaender/render-perflog

Measure long TickRender in perf.log
Merge pull request #6889 from atlimit8/ModsCommon-SystemCore

Add System.Core reference to OpenRA.Mods.Common.csproj for Linq
Added IDisabledTrait & UpgradableTrait with upgrade levels support

	IDisabledTrait for identifying (and filtering) disabled traits
	UpgradableTrait provides an abstract base for enabling trait
		by upgrade level(s)
	Added IDisabledTrait support to GlobalButtonOrderGenerator
Changed UpgradeMinLevel => UpgradeMinEnableLevel & UpgradeMaxLevel => UpgradeMaxAcceptLevel and added UpgradeMaxLevelDisables.

UpgradeMaxLevelDisables will allow stat type upgrades based on UpgradableTrait to have UpgradeMaxAcceptLevel without being disabled.
Added Exts.IsTraitEnabled for readability