Introduce multi-chain indicator

[soad003]

Tron and Ethereum use the same address format. They only encode the address differently, ethereum uses simple hex encoding, tron an encoding based on base58.

It should be trivial to show the user if the an address is also active on the other chain.

We propose an additional field in the address result holding a Dict chain: address_str if we know that the address is also active on another chain.

The situation is similar for btc and bitcoin cash.

[soad003]

This is now to some extent supported by the related addresses feature where if the pubkey is available in the database the tooling links the addresses across chains.

There are situations where the trivial check described above could still make sense. Eg. we only have a pubkey if a transaction was signed by the address. The address encoding approach would also work for addresses where no pubkey is available.