Add macros `QL_CONCEPT_OR_NOTHING` and `QL_CONCEPT_OR_TEMPLATE` #6396

Job	Run time
build (gcc, 11, -Wall -Wextra -Werror , Release, true)	3m 22s
build (gcc, 12, -Wall -Wextra -Werror , Release, true)	3m 16s
build (gcc, 13, -Wall -Wextra -Werror , Release, true)	3m 21s
build (clang, 16, -Wall -Wextra -Werror , Release, true)	3m 12s
build (clang, 17, -Wall -Wextra -Werror , Release, true)	3m 16s
build (clang, 18, -Wall -Wextra -Werror , Release, true)	3m 16s
build (gcc, 11, -DUSE_CPP_17_BACKPORTS=ON, Release)	3m 16s
build (clang, 16, RelWithDebInfo, false, -fsanitize=address -fno-omit-frame-pointer)	3m 9s
build (clang, 16, RelWithDebInfo, false, -fsanitize=undefined)	3m 17s
build (clang, 17, Debug, false, -D_NO_TIMING_TESTS=ON, -fsanitize=thread -O1 -g)	3m 13s
	32m 38s

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