Migrate to mill 0.12.5 and refactor mill scripts #3239

Job	Run time
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / ci	59s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / ci	1m 7s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / Benchmarking Sanity Check	2m 31s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / Benchmarking Sanity Check	2m 31s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / Formatting	1m 21s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / Formatting	1m 21s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / Integration Tests	13m 8s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / Integration Tests	13m 8s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / compile project with mill	4m 21s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / compile project with mill	4m 21s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / Standard Library (2.13.15)	3m 42s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / Standard Library (2.13.15)	3m 42s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / Build Mdoc & Website	7m 1s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / Build Mdoc & Website	7m 1s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / Test Scala-CLI Example / Build and Test	2m 19s
ci (ubuntu-22.04, 8, 2.13.15, 2.4, 7.0) / Test Scala-CLI Example / Build and Test	2m 19s
check tests	0s
check tests	0s
all tests passed	1s
all tests passed	1s
publish	0s
publish	0s
Deploy Website	0s
Deploy Website	0s
	1h 10m 54s

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