Create a wrapper for synedrion::KeyShare with a wasm binding

[ameba23]

Currently when running the DKG protocol on wasm, the user's keyshare is returned as a JSON encoded string.

Why is this issue relevant?

This is a bit space inefficient and does not allow the user access to useful information which can be obtained from the keyshare, eg: the verifying key (the public signing key the keyshare is used to sign messages with).

What steps are required to resolve this?

Make a type with a wasm binding which wraps synedrion::KeyShare, exposes a getter for the verifying key, and maybe includes a method to serialize it with some binary serialization, eg: bincode.

We do already have something very similar in synedrion-wasm: https://github.com/entropyxyz/synedrion/blob/c1958bce332140cd294de99f5dc6c0120fe084ca/synedrion-wasm/src/lib.rs#L50 - but i am not sure whether to use that or rather avoid having an extra dependency and just keep it in entropy-protocol.

Does this change the spec? HTTP, extrinsic, or storage? Is it breaking? Clearly describe the new interface.

This would be a breaking change to entropy-protocol wasm interface

[ameba23]

Resolved with #512