Rewrite README for clarity: smoother, more scannable, current commands #9

Job	Run time
resolve-haybarn	2s
unit (macos-latest)	13s
unit (ubuntu-latest)	15s
unit (windows-latest)	25s
integration (ubuntu-latest, haybarn_unittest-linux-amd64.zip)	19s
integration (macos-latest, haybarn_unittest-osx-arm64.zip)	20s
integration (windows-latest, haybarn_unittest-windows-amd64.zip)	52s
	2m 26s

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