[code-watcher] Add CodeWatcherMode option.

There are three option values:
- Disabled: module does nothing (wow).
- Remove: module removes matching messages and sends temporary message
          to instruct user what to do.
- Upload: module uploads detected code to configured Haste Server.

modules/CodeWatcher/Service/IHasteService.cs

@@ -0,0 +1,9 @@
+using West.TelegramBot.CodeWatcher.Dto;
+
+namespace West.TelegramBot.CodeWatcher.Service;
+
+public interface IHasteService
+{
+    public Task<HasteResponse> PostDocumentAsync(string data);
+    public Uri GetHasteUri();
+}