Support client delegate with Combine

[llbartekll]

add combine api in order to allow to register multiple subscribers on client events.

[lourenco-marinho]

Hi @llbartekll, I hope you are doing well. I'd like to know if the project is open for contribution and if so, is there any other documentation on how this api should be designed?

Thanks :)

[llbartekll]

Hey @lourenco-marinho, yes we are open for contributions. In general the api should be a substitute for a WalletConnectClientDelegate. If you'd like to contribute, please open PR to develop branch