Automatic discovery of the sliding sync proxy. (#535)

* Automatic discovery of the sliding sync proxy.

* Handle homeserver detection from a MXID.

* Update sliding sync info link, SDK and bump patch.

Add a migration on the new version. The change in restoration token format requires the user to sign in again, but this will fail with the existing device ID.

ElementX/Sources/Services/Authentication/AuthenticationServiceProxy.swift

@@ -26,7 +26,9 @@ class AuthenticationServiceProxy: AuthenticationServiceProxyProtocol {
     
     init(userSessionStore: UserSessionStoreProtocol) {
         self.userSessionStore = userSessionStore
-        authenticationService = AuthenticationService(basePath: userSessionStore.baseDirectory.path, passphrase: nil)
+        authenticationService = AuthenticationService(basePath: userSessionStore.baseDirectory.path,
+                                                      passphrase: nil,
+                                                      customSlidingSyncProxy: ServiceLocator.shared.settings.slidingSyncProxyURL?.absoluteString)
     }
     
     // MARK: - Public
@@ -51,6 +53,9 @@ class AuthenticationServiceProxy: AuthenticationServiceProxyProtocol {
             
             self.homeserver = homeserver
             return .success(())
+        } catch AuthenticationError.SlidingSyncNotAvailable {
+            MXLog.info("User entered a homeserver that isn't configured for sliding sync.")
+            return .failure(.slidingSyncNotAvailable)
         } catch {
             MXLog.error("Failed configuring a server: \(error)")
             return .failure(.invalidHomeserverAddress)

ElementX/Sources/Services/Authentication/AuthenticationServiceProxyProtocol.swift

@@ -23,6 +23,7 @@ enum AuthenticationServiceError: Error {
     case invalidServer
     case invalidCredentials
     case invalidHomeserverAddress
+    case slidingSyncNotAvailable
     case accountDeactivated
     case failedLoggingIn
 }