Use DOTNET_STARTUP_HOOKS and Harmony to hotpatch UBT and UAT, and add support for Kubernetes-based UBA

[hach-que]

Currently UET intercepts progress information by pretending to be XGE via OpenGE, which allows us to write better progress information to the terminal. Since Unreal Engine 5.4 though, Epic provides the Unreal Build Accelerator which is a replacement to XGE (and OpenGE). Not only do we want to be able to leverage UBA from UET (and distribute builds), but we need to plan for a future where XGE support is removed from the Unreal tooling since UBA exists and is recommended by Epic.

Because we can no longer pretend to be xgConsole and execute the graph ourselves, we instead need to hotpatch UBT so we can get at the internals of ActionGraph and ImmediateActionQueue, and forward all of the data we care about back to the main UET process.

• Experiment with hotpatching Kubernetes-based UBA support into UBT, so we can use it regardless of whether https://github.com/EpicGames/UnrealEngine/pull/11919 gets merged into the engine. This will also validate that our approach for DOTNET_STARTUP_HOOKS and using Harmony 2 will work.
• Hotpatch configuration reading to turn on UBA in engines that support it, and to automatically set Kubernetes UBA information from environment variables.
• Hotpatch ImmediateActionQueue constructor to retrieve total task information.
• Hotpatch ImmediateActionQueue.SetActionState to determine when an action's status has changed.
• Hotpatch ImmediateActionQueue.TryStartOneActionInternal with a transpiler patch to determine when actions start and when actions error.
• Hotpatch ImmediateActionQueue.RunTillDone so we know when the queue is complete.
• Test our hotpatching works on Unreal Engine 5.2 and 5.3. We don't need the UBA stuff to work, but we do need the ImmediateActionQueue to work so we can get progress.
• Add Redpoint.Uet.Patching.Loader project, which will replace Redpoint.Uet.OpenGE.
• Get Redpoint.Uet.Patching.Loader.csproj to bundle the output of Redpoint.Uet.Patching.Runtime and it's dependencies into an embedded resource.
• Get Redpoint.Uet.Patching.Loader to extract the bundle at runtime.
• Get Redpoint.Uet.Patching.Loader to set DOTNET_STARTUP_HOOKS to point at the extracted Redpoint.Uet.Patching.Loader.dll file.
• Define a gRPC protocol between Redpoint.Uet.Patching.Runtime and Redpoint.Uet.Patching.Loader for passing job progress.
• Get Redpoint.Uet.Patching.Runtime to pass the information collected from hotpatches back to the loader over gRPC, and then emit logging information similar to LogInterceptingDispatcher.
• Once this is working, delete all of the (now obsolete) OpenGE code.

We should then also replace the Redpoint.Uet.BuildPipeline patching code with Harmony, and avoid recompiling DLLs. This should make engine builds start much faster, and allow us to turn on UEFS-unmount-after-build to ensure cleaner build environments (currently we keep engines mounted because the .NET rebuild is too slow).

• Make sure we apply patches as a prefix to the assembly's entry point, instead of doing it immediately on startup, since non-startup assemblies aren't loaded at that point and thus Harmony won't be able to patch them yet.
• For AutomationTool, patch in BUILD_GRAPH_PROJECT_ROOT support.
• For AutomationTool, patch in BUILD_GRAPH_ALLOW_MUTATION support.
• For AutomationTool, patch script file loading so that scripts can be referenced outside the engine directory.
• For AutomationTool, patch bRemote to exclude BuildGraph targets that we know won't work with it.
• For AutomationTool, patch out robocopy-based file copies since it's unreliable.
• For EpicGames.BuildGraph, patch Switch handling so that it isn't broken with unexpected fallthroughs happening (this is fixed on modern engines, but broken for 5.0).
• For UnrealBuildTool, patch SingleInstanceMutex so that uebp_UATMutexNoWait can be used to skip it.
• For EpicGames.Build, patch WritableEngineDirectory so that includes the process ID in the UnrealEngine folder name.
• For UnrealBuildTool, patch UEDeployAndroid to fix directory name handling when paths include .uet for Gradle execution.
• Remove the old patching code.
• Enable UEFS engine dismount.