Drop less, move to lightningcss #208

Job	Run time
build (cpp, macos-latest)	1m 39s
build (jupyter, macos-latest)	1m 57s
build (js, ubuntu-latest)	1m 21s
build (python, ubuntu-latest)	39s
build (python, macos-latest)	45s
build (rust, macos-latest)	4m 56s
build (jupyter, ubuntu-latest)	2m 23s
build (rust, ubuntu-latest)	5m 40s
build (cpp, ubuntu-latest)	1m 26s
build (rustjswasm, macos-latest)	6m 51s
build (cppjswasm, ubuntu-latest)	2m 41s
build (cppjswasm, macos-latest)	2m 51s
build (rustjswasm, ubuntu-latest)	8m 9s
build (js, macos-latest)	1m 17s
	42m 35s

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