add support for multiple rmb relays in the rmb sdk

[muhamadazmy]

Is your feature request related to a problem? Please describe

rmb-peer supports connecting to multiple relays for redundancy. This feature allows the rmb-peer to continue operating if one of the relays is facing technical problems.

It also allows messages to be balanced between multiple relays.

Describe the solution you'd like

Support for multiple relays need to also be implemented in the go client

[rawdaGastan]

WIP

• Investigating twin updates on different relays when multiple relays are supported

[Omarabdul3ziz]

verified:
used my mnemonic which has only one relay configured to make an rmb call using the rmb-sdk peer and added two relays with the option WithRelay()

and my twin relays is updated, the two relays hostnames separated by _