[Depends on #8332] Integrate fgviewer to the engine side

[show50726]

This PR should be merged after #8332 is in.

In this PR, I intergrate the fgviewer to the filament engine side, right now the engine will update the framegraph info to the debug server every frame.

• Add FrameGraph::getFrameGraphInfo method to convert current state to fgviewer::FrameGraphInfo
• Add fgviewer::DebugServer member to the Engine class and initialize it as the engine loop starts
• When a view is created, register it to the fgviewer::DebugServer and unregister it as it gets terminated
• Update the info in the debug server in Renderer::renderJob after FrameGraph is compiled