xtea

feat: Implement Simon #224

Job	Run time
test (1.85.0)	20s
build (1.85.0, wasm32-unknown-unknown)	18s
test (stable)	12s
build (stable, wasm32-unknown-unknown)	16s
build (stable, thumbv7em-none-eabi)	13s
build (1.85.0, thumbv7em-none-eabi)	17s
minimal-versions / minimal-versions	17s
	1m 53s

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