Rust

Clean up bulletproof, add aggregated proofs and twisted ElGamal #3901

Job	Run time
rustfmt	17s
cargo-deny (advisories, licenses, bans, ...)	18s
test (ubuntu-ghcloud)	7m 40s
test (windows-ghcloud)	8m 43s
clippy	40s
license-check	12s
	17m 50s

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