Keep OpenEXR on version that's compatible with KImageFormats

[jdpurcell]

OpenEXR 3.3 introduced a change that broke compatibility with KImageFormats. It was fixed in KImageFormats 6.8, but even if you updated to that, you still need to keep KImageFormats 5.x compatibility for the Qt5 builds. This PR uses the overlay port capability in vcpkg to override the files for the OpenEXR port, keeping it on 3.2.4 regardless of the vcpkg commit ID in use. The port files I added in the util folder were taken from here, which is the last commit to update the port before it went to 3.3. The other way to request a specific version of a port from vcpkg is a bit more involved, so I thought you would appreciate this simpler workaround for now.

I already ran this through my Actions workflow and produced qView builds for Windows/macOS to test it, and all 5 of them (macOS Universal/x64, Windows x64/ARM64/x86) are able to load my test suite of images without regression. The only update that's needed on the qView side is to change the filename in the Windows plugin copying from lcms2.dll to lcms2-2.dll (I will PR that), which changed after an update because I bumped the vcpkgCommitId here too. vcpkg finally updated the AOM port today, by the way, so the x86 Windows build is back to completing in about ~15 minutes. 🎉

[jdpurcell]

OpenEXR fixed it on their side too in 3.3.2 which was just updated in vcpkg yesterday.