U2024.03.24-1708: Automatic merge of T1.5.1-922-g0a17d985e and 16 pull requests

- Pull request #570 at 3539862b4: Experimental glTF 2.0 support with PBR lighting
- Pull request #839 at d00beb983: First phase of https://blueprints.launchpad.net/or/+spec/additional-cruise-control-parameters
- Pull request #876 at f92de7665: docs: add source for documents previously on website to source Documentation folder
- Pull request #882 at 3ca0eb19f: Blueprint/train car operations UI window
- Pull request #885 at 42092cbfe: feat: Add notifications to Menu
- Pull request #886 at 6c0785b6c: Scene viewer extension to TrackViewer
- Pull request #892 at 1f5ba4c81: Signal Function OPP_SIG_ID_TRAINPATH
- Pull request #896 at 5866028cf: First implementation of https://blueprints.launchpad.net/or/+spec/specific-sounds-for-ai-trains
- Pull request #903 at 29f3d1a31: Downloading route content (Github, zip)
- Pull request #912 at f7b85e4bf: New Triple Valve Features Vol. 2
- Pull request #919 at 26cc6a82e: Added mouse wheel support for controls which can be moved by pressing t…
- Pull request #923 at e0f3c55d8: Add curve squeal to route
- Pull request #924 at 6c2c3cdbe: Default Asset Improvements
- Pull request #925 at e3b1688f7: Fix brakeshoe force bug
- Pull request #927 at cf687d4f4: AI Train Power Supply/Lights Fix
- Pull request #928 at 1f2351239: Fix Missing Initializations From Copy in MSTSLocomotive