Verifying external proofs

[rpalakkal]

We want to add functionality into halo2-repl to load in an external proof to verify against a vkey (either the currently loaded vkey or add the option to load in a new vkey). The existing verify function already takes in a proof array here:

halo2-browser/halo2-repl/app/page.tsx

Line 215 in 22f80b8

else await workerApi.current?.verify(proof);

Verifying external proofs should just involve adding functionality to the halo2-repl frontend to upload your own proof (and optionally your own vkey).