Implement AuthClient.request , AuthClient.pair

[bkrem]

• Create a pairing + URI as part of AuthClient.request
• Send wc_authRequest as part of AuthClient.request (i.e. this.sendRequest(pairingTopic, "wc_authRequest",...)). Can use dummy payload for now.
• Implement AuthClient.pair on responder side to process URI input and subscribe to pairing topic

Goals

• Requester can generate URI as part of AuthClient.request and return it, so it can be shared with the responder out-of-band.
• Responder can process a URI input and subscribe to the provided pairing topic
• Responder can receive the wc_authRequest issued by the requester via the pairing topic.
• We are able to validate this behaviour via the unit tests.