Support host-side `keccak256` hashing

[zie1ony]

It would be useful for this ffi: casper_generic_hash to support keccak256.

[mssteuer]

@EdHastingsCasperAssociation can we discuss this sometime next week?

[devendran-m]

Hi @zie1ony ,
cc: @mssteuer , @EdHastingsCasperAssociation ,

This has been prioritised in the sprint cycle CW23, i.e. 15 to 29 July '25.
Internal Jira ticket for this issue is CORE-151.