feat: add native rust implementation of schnorr signature verification

[TomAFrench]

Description

Problem*

Resolves

Summary*

This PR replaces the final wasm calls to barretenberg with a native implementation of schnorr signature verification. This allows us to remove the entire acvm_backend.wasm.

This schnorr implementation is something this I've slapped together in an afternoon so be warned of potential bugs, there doesn't seem to be any off-the-shelf rust implementations of schnorr using grumpkin however.

Now we don't need to do wasm initialisation for acvm_js, we can stop caching a solver object to pass into acvm_js, I've maintained the interface for now however but the external solver is ignored.

Benchmarks relative to #5056

schnorr_verify          time:   [526.91 µs 527.81 µs 528.91 µs]
                        change: [-67.185% -67.081% -66.993%] (p = 0.00 < 0.05)
                        Performance has improved.

Additional Context

Documentation*

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.