refactor!: nuke top level await

[olehmisar]

Closes #9959

May be postponed if #9987 makes performance acceptable.

Removed top-level await. BarretenbergSync.getSingleton and all functions and methods that depend on it are now marked as async.

Changes

• FunctionSelector.equals cannot accept string and { name: string; parameters: ABIParameter[] } anymore. Otherwise it has to be async as well
• EntrypointPayload, AppEntrypointPayload, and FeeEntrypointPayload are worth taking closer look at as they were changed more than other classes
• Carefully review orchestrator.ts in prover-client because i have no idea what that code is
• await wallet.setPublicAuthWit({ caller, action }, true).send().wait() is now await (await wallet.setPublicAuthWit({ caller, action }, true).send()).wait()
• contract.methods.xxx.selector now returns a Promise<FunctionSelector>

There may be bugs introduced

• if functions that previously returned boolean were changed to return Promise and now they always return truthy values (because Promise is truthy)
• if functions that previously thrown an error synchronously were changed to async and now they throw asynchronously, so it breaks the flow

[olehmisar]

still countless errors to fix

[ludamad]

@charlielye any comments on the approach of mass-asyncifying bb?

[olehmisar]

everything except end-to-end typechecks. Waiting whether this PR is even gonna be merged before continuing. Also, see the PR description for substantial changes and potential bugs introduced.