[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/HasteService.cs

@@ -0,0 +1,32 @@
+using System.Net.Http.Json;
+using West.TelegramBot.CodeWatcher.Dto;
+
+namespace West.TelegramBot.CodeWatcher.Service;
+
+public class HasteService : IHasteService
+{
+    private readonly HttpClient _client;
+
+    public HasteService(HttpClient client)
+    {
+        _client = client;
+    }
+
+    public async Task<HasteResponse> PostDocumentAsync(string data)
+    {
+        var response = await (await _client.PostAsync("documents", new StringContent(data)))
+            .Content.ReadFromJsonAsync<HasteResponse>();
+
+        if (response == null)
+        {
+            throw new Exception("Haste returned some shit");
+        }
+
+        return response;
+    }
+
+    public Uri GetHasteUri()
+    {
+        return _client.BaseAddress!;
+    }
+}