ROS#160: Moved `critical-section` to Aerugo, removed from HAL #241

Job	Run time
Check formatting	22s
Clippy	5m 25s
Build (thumbv7em-none-eabihf, use-aerugo-cortex-m)	28s
Build (x86_64-unknown-linux-gnu, use-aerugo-x86)	26s
Build examples	1m 46s
Generate docs	32s
Run tests	1m 35s
Build HAL integration tests	55s
	11m 29s

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