* Add IVCProof to the existing folding schemes (Nova,HyperNova,ProtoGalaxy)

* Implement `from_ivc_proof` for the FoldingSchemes trait (and Nova,
HyperNova, ProtoGalaxy), so that the FoldingScheme IVC's instance can be
constructed from the given parameters and the last IVCProof, which
allows to sent the IVCProof between different parties, so that they can
continue iterating the IVC from the received IVCProof.  Also the
serializers allow for the IVCProof to be sent to a verifier that can
deserialize it and verify it.

This allows to remove the logic from the file
[folding/nova/serialize.rs](f1d82418ba/folding-schemes/src/folding/nova/serialize.rs)
and
[folding/hypernova/serialize.rs](f1d82418ba/folding-schemes/src/folding/hypernova/serialize.rs)
(removing the whole files), which is now covered by the `IVCProof`
generated serializers (generated by macro instead of handwritten), and
the test that the file contained is now abstracted and applied to all
the 3 existing folding schemes (Nova, HyperNova, ProtoGalaxy) at the
folding/mod.rs file.

* update Nova VerifierParams serializers to avoid serializing the R1CS to save big part of the old serialized size

* rm .instances() since it's not needed

* add nova params serialization to nova's ivc test to ensure that IVC verification works with deserialized data

* Add unified FS::ProverParam & VerifierParam serialization & deserialization (for all Nova, HyperNova and ProtoGalaxy), without serializing the R1CS/CCS and thus saving substantial serialized bytes space.

* rm CanonicalDeserialize warnings msgs for VerifierParams

* feat: enable hiding commitments in nova and hypernova

* fix: set blinding values for witness vector

* fix: remove cloning of the cyclefold running instance

* fix: do not re-use blinding values between prove steps

* fix: specify whether the witness should use blinding values using a
const generic

* feat: create a `dummy` method for nova witnesses as well

* chore: clippy - removed unused imports

- Adds the logic to support multi-instances folding in HyperNova's
AugmentedFCircuit & IVC.
- Adds also methods to generate new LCCCS & CCCS instances that don't
depend on the main folding chain, to be folded in in the next step
- Updates CycleFold circuit & methods to work other folding schemes than
  Nova, adapting it to fold multiple points per circuit (instead of
2-to-1 as till now)
- Handle multi-instances folding in the FoldingScheme trait
  interface, which expects 'None' in Nova, and 'Some' in HyperNova &
other multi-folding schemes.

- implement hash of public params for Nova & HyperNova
- abstract pp_hash computation for folding schemes
- add pp_hash to solidity contract generator to verify the decider proof

- implement the IVC `FoldingScheme` trait for HyperNova
- refactor Nova's preprocess logic to make it simplier to use
- add to Decider trait (& Nova's DeciderEth) a preprocess method
- get rid of the `init_nova_ivc_params` and `init_ivc_and_decider_params` methods in `examples` since this is achieved with the `FS::preprocess` & `Decider::preprocess` methods
  - (update the examples code to the simplified interface using
    FS::preprocess & Decider::preprocess)

* circom: add external_inputs

* adapt new external_inputs interface to the FoldingScheme trait and Nova impl

* adapt examples to new FCircuit external_inputs interface

* add state_len & external_inputs_len params to CircomFCircuit

* add examples/circom_full_flow.rs

* merge the params initializer functions, clippy

* circom: move r1cs reading to FCircuit::new instead of each step

* CI/examples: add circom so it can run the circom_full_flow example

* expose params & structs for external usage

* add full_flow example, move examples into 'examples' dir

* Add external inputs logic to F function/circuit. Add an example of usage with external inputs too.

* Add examples run into CI

* Add typos to CI

* Apply typos suggestions

* missing typos

* Fix Nova multi-elements state

In the AugmentedFCircuit the default value for the state when no input
is provided was `vec![F::zero()]`, which defaults to length `1`. So when
having more than 1 element in the state, before even starting to fold,
the circuit was already already failing.

Additionally this commit adds an example for a circuit with a state of 5
elements.

* abstract 'nova_setup' helper to avoid code duplication in examples

* update example naming to 'MultiInputs'

* rename nova_setup -> test_nova_setup to make it more explicit