Explore ways to support multiple client libraries

[spsjvc]

Currently, in order to use the Arbitrum SDK in your project, you have to use ethers@v5, as a lot (if not all) SDK methods accept and receive ethers@v5 objects, like Signer, Provider, TransactionReceipt etc.

Ideally, we should be able to support using any of them, e.g. ethers@v5, ethers@v6, viem, web3.js etc, while continuing to use ethers for our implementation. Maybe we could reduce the dependencies to the minimum interfaces needed, and then write small adapters that map objects from different libraries to the shared interfaces? It would be cool if the user could just "pick" an adapter once when configuring the library without having to do it at every call site.

As a PoC, we could try doing so for a couple of read and write methods:

• https://github.com/OffchainLabs/arbitrum-sdk/blob/main/src/lib/assetBridger/erc20Bridger.ts#L218
• https://github.com/OffchainLabs/arbitrum-sdk/blob/main/src/lib/assetBridger/ethBridger.ts#L179

This is a huge breaking change so probably targets v4, but worth exploring.