Move Poseidon primitive into `halo2_poseidon` #4067

Job	Run time
Bitrot check	1m 28s
Book tests	1m 27s
Build target wasm32-unknown-unknown	1m 51s
Build target wasm32-wasi	1m 42s
Code coverage	3m 34s
Intra-doc links	1m 31s
Rustfmt	13s
Test on ubuntu-latest	1m 52s
Test on windows-latest	1m 49s
Test on i686-unknown-linux-gnu	12m 52s
Test on macOS-latest	15s
Test on i686-unknown-linux-gnu with beta features	13m 24s
Test on ubuntu-latest with beta features	1m 51s
Test on i686-unknown-linux-gnu with nightly features	15m 2s
Test on windows-latest with beta features	1m 51s
Test on macOS-latest with beta features	1m 54s
Test on ubuntu-latest with nightly features	1m 50s
Test on windows-latest with nightly features	1m 51s
Test on macOS-latest with nightly features	1m 46s
	1h 8m 3s

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