Add Hash name to the Domain Separator

[mmaker]

We expect to potentially use two hash functions in the domain separator:

• Keccak in duplex overwrite mode
• Keccak in duplex mode

since there exists a reduction from one to the other, it is important when considering multi-protocol security that these two lead to different IVs.

[omibo]

I’m interested in working on this issue if it’s still available.

[mmaker]

Please go ahead and give it a try!

[Saksham010]

Still available?

[mmaker]

@Saksham010 yes, sorry for the late reply! can you please start by adding a const 'static str to the DuplexSpongeInterface?