Implement support for new Steam chat (#811)

* First proof of concept

Still missing friends interaction

* Misc

* Add missing bits

* Misc

* Misc

* Misc

* Misc

* Handle new max message length

* AH bits for messages ack

* Implement MarkReceivedMessagesAsRead

* Mark notifications appropriately

* Remove obsolete callback subscriptions

* Correct NoResponse functions

* Adapt new code to beta format

* Implement advanced chat logging functionality

* Improve message handling

* Port naive escaping logic from ArchiBoT

* Cover edge cases

* Update lib

* Misc

* Kill more obsolete pragmas

* Update SK2 to official build

From https://ci.appveyor.com/project/SteamRE/steamkit/build/2.1.0.649/job/osamyjpyf7v9ot7k/artifacts

* Packages update

* SteamTarget changes

Single responsibility + fix of required parameters

ArchiSteamFarm/Program.cs

@@ -323,12 +323,9 @@ namespace ArchiSteamFarm {
 				return;
 			}
 
+			// If debugging is on, we prepare debug directory prior to running
 			if (Debugging.IsUserDebugging) {
 				ASF.ArchiLogger.LogGenericDebug(SharedInfo.GlobalDatabaseFileName + ": " + JsonConvert.SerializeObject(GlobalDatabase, Formatting.Indented));
-			}
-
-			// If debugging is on, we prepare debug directory prior to running
-			if (GlobalConfig.Debug) {
 				Logging.EnableTraceLogging();
 
 				if (Directory.Exists(SharedInfo.DebugDirectory)) {