Improvements to logging (#457)

* Use `.info` logging in most places.
* Remove old objc logging support.
* Fix table view controller.
* Make sure timeline item content isn't logged.
* Add tests.

NSE/Sources/Other/UNMutableNotificationContent.swift

@@ -32,7 +32,7 @@ extension UNMutableNotificationContent {
                                                           options: nil)
             attachments.append(attachment)
         case .failure(let error):
-            MXLog.debug("Couldn't add media attachment: \(error)")
+            MXLog.error("Couldn't add media attachment: \(error)")
         }
         
         return self
@@ -81,10 +81,11 @@ extension UNMutableNotificationContent {
             // Update notification content before displaying the
             // communication notification.
             let updatedContent = try updating(from: intent)
-
+            
+            // swiftlint:disable:next force_cast
             return updatedContent.mutableCopy() as! UNMutableNotificationContent
         case .failure(let error):
-            MXLog.debug("Couldn't add sender icon: \(error)")
+            MXLog.error("Couldn't add sender icon: \(error)")
             return self
         }
     }