replace waypoint pointers with waypoint indexes #4655

Job	Run time
Windows (Debug, MSVC, Win32)	9m 57s
Mac (Debug, clang, x86_64)	5m 18s
Windows (Debug, MSVC, x64)	12m 2s
Linux (Debug, gcc-9)	11m 14s
Mac (Debug, clang, arm64)	5m 27s
Windows (Release, MSVC, Win32)	18m 15s
Linux (Debug, gcc-13)	8m 46s
Mac (Release, clang, x86_64)	5m 22s
Windows (Release, MSVC, x64)	19m 41s
Linux (Debug, clang-16)	13m 0s
Mac (Release, clang, arm64)	7m 19s
Linux (Release, gcc-9)	7m 10s
Linux (Release, gcc-13)	8m 21s
Linux (Release, clang-16)	12m 40s
Linux (Debug, gcc-13, -DFSO_BUILD_WITH_OPENGL=OFF -DFSO_BUILD_WITH_VULKAN=OFF)	9m 37s
Linux (Release, gcc-13, -DFSO_BUILD_WITH_OPENGL=OFF -DFSO_BUILD_WITH_VULKAN=OFF)	8m 10s
	2h 42m 19s

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