UnrealBuild -> Unreal for EngineDirectory, RootDirectory, IsEngineInstalled, UnrealBuildToolPath
Remove CommandUtils EngineDirectory, RootDirectory, IsEngineInstalled - use equvalents from UnrealBuildBase.Unreal
#jira none
[CL 16648181 by jonathan adamczewski in ue5-main branch]
RootDirectory, EngineDirectory, UnrealBuildToolPath are now found in BuildUtilities' UnrealBuild namesapce.
The way these are computed has changed. Previously, it was assumed that the application is UnrealBuildTool, and paths were constructed relative to that assembly.
Now, the assumption is that the process is located under a "Engine/Build/DotNET" sub-path and paths are constructed relative to that.
#jira none
[CL 16607440 by jonathan adamczewski in ue5-main branch]
