feat(group.ts): add static method `toInput` for Group instance #3462

Job	Run time
Build-And-Test-Web	4m 36s
Build-And-Test-Server (Simple integration tests)	17m 31s
Build-And-Test-Server (DEX integration tests)	13m 29s
Build-And-Test-Server (DEX integration test with proofs)	13m 10s
Build-And-Test-Server (Voting integration tests)	5m 18s
Build-And-Test-Server (Unit tests)	44m 17s
Build-And-Test-Server (Verification Key Regression Check)	11m 37s
Build-And-Test-Server (CommonJS test)	2m 28s
Release-mina-signer-on-NPM	1m 50s
Release-on-NPM	1m 46s
	1h 56m 2s

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