[opencv4] Missing feature for "carotene"

The opencv4 port is missing a feature for "carotene" and the corresponding WITH_CAROTENE flag passed to OpenCV.

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Is your feature request related to a problem? Please describe. When building an Android project that consumes opencv4 (targeting armeabi-v7a or arm64-v8a from vcpkg), I get a bunch of linker errors like this:

error: undefined reference to 'carotene_o4t::isSupportedConfiguration()'
error: undefined reference to 'carotene_o4t::add(carotene_o4t::Size2D const&, unsigned char const*, int, unsigned char const*, int, unsigned char*, int, carotene_o4t::CONVERT_POLICY)'
...

Proposed solution A feature for "carotene" should be added to the CONTROL and portfile.cmake so that folks can enable or disable the feature appropriately.

Describe alternatives you've considered To unblock myself for now, I've added a brittle workaround to my triplet file that takes advantage of the fact that vcpkg_configure_cmake takes an additional variable called ADDITIONAL_BUILD_FLAGS:

if(PORT MATCHES "opencv")
    list(APPEND ADDITIONAL_BUILD_FLAGS "-DWITH_CAROTENE=OFF")
endif()

Resolved by #42745.