Create better blockchain balance provider setup, for security and resilience

New provider methods:

• provider.eth.getBalance
• provider.eth.getMultipleBalances
• provider.isSupported = bool (if needs api key, if has SDK etc)

Needs a main request class:

• Allow multiple providers [JSON RPC, apis]
• hit each provider in priority order
• detect if the request is erroring, then move to next
• prioritize on security -- RPC, paid API, Free APIs