#688: Move utils_instance_or_reference_wrapper.hpp to `solvers_nonlinear` #305

Job	Run time
baseline (fedora-clang-17, Release)	12m 17s
baseline (fedora-clang-17, Debug)	9m 0s
baseline (fedora-gnu-13, Release)	11m 18s
baseline (fedora-gnu-13, Debug)	9m 17s
baseline (ubuntu-clang-14, Release)	11m 54s
baseline (ubuntu-clang-14, Debug)	9m 36s
baseline (ubuntu-gnu-11, Release)	10m 17s
baseline (ubuntu-gnu-11, Debug)	8m 56s
baseline (ubuntu-gnu-11, Release, -D CMAKE_CXX_STANDARD=20 -D PRESSIO_ENABLE_CXX20=ON)	11m 18s
baseline (ubuntu-clang-14, Release, -D CMAKE_CXX_STANDARD=20 -D PRESSIO_ENABLE_CXX20=ON)	12m 59s
baseline (fedora-gnu-13, Release, -D CMAKE_CXX_STANDARD=20 -D PRESSIO_ENABLE_CXX20=ON)	12m 26s
baseline (fedora-clang-17, Release, -D CMAKE_CXX_STANDARD=20 -D PRESSIO_ENABLE_CXX20=ON)	13m 59s
	2h 13m 17s

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