Add Wasm Proof, rename Signature structs to Proof

[cycraig]

Description of change

Renames Signature, SignatureValue, and SignatureOptions to Proof, ProofValue and ProofOptions respectively. This is to avoid duplicate Signature definitions conflicting in the Wasm bindings.

Also adds Wasm bindings for Proof to avoid returning the any type in WasmDocument and WasmDiffMessage. Also changes the type of properties in CreateServiceOptions to avoid any.

Added

• Add WasmProof.

Changed

• Change WasmDocument.proof() return from any to WasmProof.
• Change WasmDiffMessage.proof() return from any to WasmProof.
• Rename Signature to Proof.
• Rename SignatureValue to ProofValue.
• Rename SignatureOptions to ProofOptions.
• Rename TrySignature to GetSignature.
• Rename TrySignatureMut to GetSignatureMut.

Removed

• Remove TrySignature::try_signature.
• Remove TrySignatureMut::try_signature_mut.

Type of change

• Bug fix (a non-breaking change which fixes an issue)
• Enhancement (a non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Fix

How the change has been tested

Wasm tests and examples pass locally.

Change checklist

• I have followed the contribution guidelines for this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[abdulmth]

Looks good to me, just wondering if renaming GetSignature to GetProof makes sense, same for GetSignatureMut

[cycraig]

wondering if renaming GetSignature to GetProof makes sense, same for GetSignatureMut

I'm not too fussed on leaving those as GetSignature since they're mostly for internal use (but have to be public). My reasoning for leaving them as GetSignature is that they're used within the Sign and Verify traits, where the term makes more sense than proof.