Allow for passing multiple RPC URLs

Currently, the Verifying provider is booted up with just one provider. This provider can be malicious in such a case the current system simply throws an error and fails.

Allow for passing a set of RPC URLs ordered by the most trusted one first. Gracefully try other provider URLs sequentially

Start by tracing how the Verifying provider is initialized with its single provider and where provider errors are handled. Check the existing RPC proxy flow before deciding how the ordered URLs are passed. Done means the most trusted URL is tried first, failures are handled gracefully, and later URLs are tried sequentially.

Written by the indexing model from the issue text.