Add `universalaccess.reduceMotion` option #1208

Job	Run time
install-against-stable	3m 6s
install-against-unstable	3m 51s
install-flake-against-stable	3m 21s
install-flake-against-unstable	2m 54s
test-stable	3m 49s
test-unstable	10m 36s
	27m 37s

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