Refactor the `features` module #1648

Job	Run time
docs	26s
minimal	14s
msrv	1m 32s
check-cfg	31s
quickchecking	25s
rustfmt-clippy	47s
test-book	13s
test (ubuntu-latest, 5.0, 1, 0, 0, 0, 0)	3m 24s
test (ubuntu-latest, 5.0, 1, 0, 0, 1, 0)	3m 2s
test (ubuntu-latest, 5.0, 1, 0, 1, 0, 0)	2m 43s
test (ubuntu-latest, 5.0, 1, 0, 1, 1, 0)	2m 37s
test (ubuntu-latest, 5.0, 1, 1, 0, 0, 0)	3m 42s
test (ubuntu-latest, 5.0, 1, 1, 0, 1, 0)	3m 31s
test (ubuntu-latest, 5.0, 1, 1, 1, 0, 0)	3m 21s
test (ubuntu-latest, 5.0, 1, 1, 1, 1, 0)	4m 36s
test (ubuntu-latest, 9.0, 1, 0, 0, 0, 0)	3m 57s
test (ubuntu-latest, 9.0, 1, 0, 0, 1, 0)	3m 11s
test (ubuntu-latest, 9.0, 1, 0, 1, 0, 0)	3m 0s
test (ubuntu-latest, 9.0, 1, 0, 1, 1, 0)	3m 54s
test (ubuntu-latest, 9.0, 1, 1, 0, 0, 0)	3m 42s
test (ubuntu-latest, 9.0, 1, 1, 0, 1, 0)	5m 0s
test (ubuntu-latest, 9.0, 1, 1, 1, 0, 0)	4m 27s
test (ubuntu-latest, 9.0, 1, 1, 1, 1, 0)	3m 50s
test (ubuntu-latest, 9.0, 0, 0, 1)	1m 55s
test (macos-latest, 9.0, 0, 0, 0)	2m 5s
test-expectations (ubuntu-latest)	2m 1s
test-expectations (macos-latest)	4m 0s
	1h 12m 6s

Provide feedback