Add ENS support

[ArtificialPB]

Module

Providers

📝 Description

Add support for resolving ENS addresses, and allow setting transaction recipients as ENS addresses. We should probably introduce a new sealed type for this, e.g. AddressOrName/AddressOrENS.

References:

• https://github.com/hhatto/rust-ens
• Provider impl.: https://github.com/gakonst/ethers-rs/blob/master/ethers-providers/src/rpc/provider.rs#L1155-L1231
• ENS: https://github.com/gakonst/ethers-rs/blob/master/ethers-providers/src/ext/ens.rs

[ArtificialPB]

Done via 11b34fd