Sponge API refactor

[tessico]

Description

This is a WIP.

The refactor defines new explicit types for CRHF and PRF which are sponges that internally use the Rescue Permutation, and as such is more aligned with the CAPE spec.

By following the sponge API we are able to re-use code shared between the above two functionalities.

It should then be then easier to make the circuits more generic by also defining and implementing a trait like CryptographicSpongeVar, though we'd probably need to define our own due to a dependency on a R1CS ConstraintSystem.

closes: #15

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• Targeted PR against correct branch (main)
• Linked to GitHub issue with discussion and accepted design OR have an explanation in the PR that describes this work.
• Wrote unit tests
• Updated relevant documentation in the code
• Added a relevant changelog entry to the Pending section in CHANGELOG.md
• Re-reviewed Files changed in the GitHub PR explorer

[tessico]

Btw, it goes a little further than #50, in that it also uses the new absorb/squeeze methods in the encapsulating types' implementation of full_state_keyed_sponge, sponge_no_padding etc.

[tessico]

@EspressoSystems/jellyfish

[mrain]

Good work 👍 Rescue interface looks cleaner now.
There are a few questions left.

[alxiong]

I like the refactoring! being explicit about what we are using Rescue for is very good.

• IMO, RescueSpongeCRHF should be RescueSpongeCRH or even simpler RescueCRH

[tessico]

@EspressoSystems/jellyfish This should be ready for a (hopefully) final round of reviews!

[mrain]

Generally LGTM. Could you add some lines in CHANGELOG.md under PENDING section?

[mrain]

LGTM!