Track ETH and SOL addresses

We updated the Track endpoint

address_type is not required anymore. It was used for SOL to specify either a stake account or a wallet. The former was not used, so we removed the option. Its behavior is streamlined: you track a wallet and we auto track all stake accounts for which this wallet is the stake authority.

Same for ETH: you cannot track a single validator anymore, only a wallet that we interpret as the validators' withdrawal address