Eliminate deprecated RPC methods

[steveluscher]

The following deprecated methods are being removed in Agave 2.0:

• confirmTransaction
• getSignatureStatus
• getSignatureConfirmation
• getTotalSupply
• getConfirmedSignaturesForAddress
• getConfirmedBlock
• getConfirmedBlocks
• getConfirmedBlocksWithLimit
• getConfirmedTransaction
• getConfirmedSignaturesForAddress2
• getRecentBlockhash
• getFees
• getFeeCalculatorForBlockhash
• getFeeRateGovernor
• getSnapshotSlot

Clean all references and code for these from web3.js.

[steveluscher]

I've started to have a few second thoughts here.

1. Responsibly removing these methods would require a major version bump, which would take legacy web3.js to 2.0.
2. The new library that we actually intend on releasing as web3.js 2.0 already has these methods gone.

I think maybe we just cut our losses for legacy, and close #2859 by releasing the new library. Two birds, one stone.