Remove unused code

Sources/ElixxirDAppsSDK/Models/UserDiscoveryEnvironment.swift

-import Foundation
-
-public struct UserDiscoveryEnvironment: Equatable {
-  public init(
-    address: String,
-    cert: Data,
-    contact: Data
-  ) {
-    self.address = address
-    self.cert = cert
-    self.contact = contact
-  }
-
-  public var address: String
-  public var cert: Data
-  public var contact: Data
-}