``createClient`` should return the clientID

[lightyear15]

function createClient should return a string with the clientID just created.

[bluele]

Thanks! Also, in order for the relayer to get a new clientID, it is better to emit an event containing it as well as ibc-go. https://github.com/cosmos/ibc-go/blob/83315a90626edec5ec876d438c532a48c4e806be/modules/core/keeper/msg_server.go#L44

[bluele]

NOTE: we need to fix this for Connection and Channel as well

[bluele]

Currently, it has already implemented:

• https://github.com/hyperledger-labs/yui-ibc-solidity/blob/d518aaaa8c7cbb231f52efa26cc658bdf39b307c/contracts/core/25-handler/IBCClientHandler.sol#L38
• https://github.com/hyperledger-labs/yui-ibc-solidity/blob/d518aaaa8c7cbb231f52efa26cc658bdf39b307c/contracts/core/25-handler/IBCConnectionHandler.sol#L15
• https://github.com/hyperledger-labs/yui-ibc-solidity/blob/d518aaaa8c7cbb231f52efa26cc658bdf39b307c/contracts/core/25-handler/IBCChannelHandler.sol#L39