Chain Switching at Runtime

[kantagara]

Summary
Add the ability to switch chains at runtime.

Suggested features or ways to address the summary

• Add an easy way for developers to switch between various chains. In my opinion, the whole web3 instance should've been built from the ground up then (ISigner and ITransactionExecutor should be the same but RPC Provider should have to be reinitialized somehow).

Motivation

• We got a lot of requests to provide such a thing.

Acceptance Criteria

• you can switch from one chain to the other without a hassle.