[fcl] Adds WalletConnect Adapter Package and support for client plugin services

[gregsantos]

In order to add support for WalletConnect and other client configured authentication services, FCL can use a service plugin registry or config to extend it's service methods. Client configured services, including extensions and plugins can be sent to Discovery for display and selection by the user.

import * as fcl from '@onflow/fcl'
import { initFclWc } from '@onflow/fcl-wc'

const { FclConnectServicePlugin, client } = await initFclWc({
  projectId: PROJECT_ID
})

fcl.pluginRegistry.add(FclConnectServicePlugin)

A Discovery Service Plugin should be an object consist of a name: String, type: String, discoveryServices: Array.
Each service needs a service definition of f_type: "Service" and a corresponding service strategy for the service definition's Method.
A Service strategy should return a function that returns a Promise that resolves to a PollingResponse.

name: "fcl-service-walletconnect",
type: "discovery-service",
dicoveryServices: [
    {
      definition: {
        f_type: "Service",
        f_vsn: "1.0.0",
        type: "authn",
        method: "WC/RPC",
        uid: "wc#authn",
        endpoint: "flow_authn",
        optIn: false,
        provider: {
          address: "WalletConnect",
          name: "WalletConnect",
          uid: null,
          icon: "https://avatars.githubusercontent.com/u/37784886",
          description: "WalletConnect Generic Provider",
          website: "https://walletconnect.com/",
          color: null,
          supportEmail: null,
        },
      },
      strategy: Promise,
    }

pluginRegistry.add will accept one or an array of plugins of type "discovery-service"

[gregsantos]

@JeffreyDoyle We need the topic id from an existing paired wallet. This topic is sent with the wallet connect request, to skip QR code.
I added it to a new field on the generated service -> provider.uid
This should work, but we also need each service generated to have a different address I think.

resolved for alpha