feat: replace solang with solar (#215) #803

Job	Run time
doctest	1m 42s
feature-checks	3m 44s
docs	1m 7s
clippy	1m 17s
fmt	14s
test stable (ubuntu-latest)	1m 22s
test stable --all-features (ubuntu-latest)	2m 23s
test 1.70 (ubuntu-latest)	57s
test stable (macos-latest)	1m 47s
test stable --all-features (macos-latest)	2m 30s
test 1.70 (macos-latest)	1m 45s
test stable (windows-latest)	3m 24s
test stable --all-features (windows-latest)	5m 59s
test 1.70 (windows-latest)	3m 15s
	31m 26s

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